U.S. patent number 10,333,757 [Application Number 15/383,218] was granted by the patent office on 2019-06-25 for fbmc-based pilot sending method, channel estimation method, and related apparatuses.
This patent grant is currently assigned to Huawei Technologies Co., Ltd.. The grantee listed for this patent is HUAWEI TECHNOLOGIES CO., LTD.. Invention is credited to Lei Min, Guangmei Ren, Hua Yan.
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United States Patent |
10,333,757 |
Ren , et al. |
June 25, 2019 |
**Please see images for:
( Certificate of Correction ) ** |
FBMC-based pilot sending method, channel estimation method, and
related apparatuses
Abstract
The present disclosure provides an FBMC-based pilot sending
method, a channel estimation method, and a related apparatus. The
FBMC-based pilot sending method includes: for each transmit antenna
port, inserting a pilot symbol group at four consecutive FBMC
time-frequency resource locations, where the pilot symbol group
includes two auxiliary pilot symbols and two primary pilot symbols;
calculating a transmit value of each auxiliary pilot symbol in the
pilot symbol group according to obtained interference coefficient
values and obtained transmit values of data symbols at
time-frequency resource locations in a time-frequency resource
location range in which each primary pilot symbol is interfered
with; and sending the pilot symbol group, where the pilot symbol
group includes the calculated transmit values of the auxiliary
pilot symbols.
Inventors: |
Ren; Guangmei (Chengdu,
CN), Yan; Hua (Chengdu, CN), Min; Lei
(Shenzhen, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
HUAWEI TECHNOLOGIES CO., LTD. |
Shenzhen |
N/A |
CN |
|
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Assignee: |
Huawei Technologies Co., Ltd.
(Shenzhen, CN)
|
Family
ID: |
54936474 |
Appl.
No.: |
15/383,218 |
Filed: |
December 19, 2016 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170099172 A1 |
Apr 6, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/CN2014/080808 |
Jun 26, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L
5/0005 (20130101); H04L 27/264 (20130101); H04L
25/0202 (20130101); H04L 27/261 (20130101); H04L
27/26 (20130101); H04L 5/0048 (20130101) |
Current International
Class: |
H04L
12/28 (20060101); H04L 27/26 (20060101); H04L
5/00 (20060101); H04L 25/02 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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101877689 |
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Nov 2010 |
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CN |
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103368889 |
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Oct 2013 |
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CN |
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2713542 |
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Apr 2014 |
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EP |
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2008007019 |
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Jan 2008 |
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WO |
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2013121958 |
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Aug 2013 |
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WO |
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Other References
International Search Report issued in International Application No.
PCT/CN2014/080808 dated Mar. 30, 2015, 4 pages. cited by applicant
.
3GPP TSG RAN WG1#43 R1-051458,"Some practical aspects for OFDM/OQAM
channel estimation", France Telecom, Nov. 7-11, 2005; 6 pages.
cited by applicant .
Lele et al.,"Channel Estimation With Scattered Pilots in
OFDM/OQAM", Signal Processing Advances in Wireless Communications,
2008; 5 pages. cited by applicant .
Yoon et al.,"Pilot Structure for high Data Rate in OFDM/OQAM-IOTA
System", Vehicular Technology Conference, 2008; 5 pages. cited by
applicant .
Kliks et al.,"Power Loading for FBMC Systems: An Analysis with
Mercury-filling Approach", ICT 2013, IEEE, May 6, 2013; 5 pages.
cited by applicant .
Extended European Search Report issued in European Application No.
14896060.2 dated Nov. 2, 2017; 11 pages. cited by
applicant.
|
Primary Examiner: Tran; Phuc H
Attorney, Agent or Firm: Fish & Richardson P.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of International Application No.
PCT/CN2014/080808, filed on Jun. 26, 2014, the disclosure of which
is hereby incorporated by reference in its entirety.
Claims
What is claimed is:
1. An FBMC-based pilot sending method, comprising: for each
transmit antenna port, inserting a pilot symbol group at four
consecutive FBMC time-frequency resource locations, wherein the
pilot symbol group comprises two auxiliary pilot symbols and two
primary pilot symbols; for each primary pilot symbol, determining a
time-frequency resource location range in which the primary pilot
symbol is interfered with; for each primary pilot symbol, obtaining
transmit values of data symbols at time-frequency resource
locations in the determined time-frequency resource location range
in which the primary pilot symbol is interfered with; for each
primary pilot symbol, obtaining, according to multiplex converter
response data, interference coefficient values of interference
caused at the time-frequency resource locations to the primary
pilot symbol, wherein the time-frequency resource locations are in
the determined time-frequency resource location range corresponding
to the primary pilot symbol; calculating a transmit value of each
auxiliary pilot symbol in the pilot symbol group according to the
obtained interference coefficient values and the obtained transmit
values of the data symbols at the time-frequency resource locations
in the time-frequency resource location range in which each primary
pilot symbol is interfered with; and sending the pilot symbol
group, wherein the pilot symbol group comprises the calculated
transmit values of the auxiliary pilot symbols.
2. The method according to claim 1, wherein the inserting a pilot
symbol group at four consecutive FBMC time-frequency resource
locations comprises: respectively inserting a first auxiliary pilot
symbol, a first primary pilot symbol, a second primary pilot
symbol, and a second auxiliary pilot symbol at a K.sup.th, a
(K+1).sup.th, a (K+2).sup.th; and a (K+3).sup.th FBMC symbol
locations on a same subcarrier at the time-frequency resource
locations, wherein K is a natural number; or respectively inserting
a first auxiliary pilot symbol, a first primary pilot symbol, a
second primary pilot symbol, and a second auxiliary pilot symbol on
a N.sup.th, (N+1).sup.th, a (N+2).sup.th, and a (N+3).sup.th FBMC
subcarriers at a same FBMC symbol location at the time-frequency
resource locations, wherein N is a natural number.
3. The method according to claim 1, wherein the calculating a
transmit value of each auxiliary pilot symbol in the pilot symbol
group according to the obtained interference coefficient values and
the obtained transmit values of the data symbols at the
time-frequency resource locations in the time-frequency resource
location range in which each primary pilot symbol is interfered
with comprises: for an auxiliary pilot symbol adjacent to the
primary pilot symbol in the pilot symbol group, adding up values
obtained after separately multiplying the obtained transmit values
of the data symbols corresponding to the primary pilot symbol by
the interference coefficient values of the interference caused at
the time-frequency resource locations of the data symbols to the
primary pilot symbol, and using the calculated added result as a
first result; dividing the first result by an interference
coefficient value of interference caused at a time-frequency
resource location of the auxiliary pilot symbol to the primary
pilot symbol, and using the calculated result as a second result;
and determining a value obtained after the second result is negated
as the transmit value of the auxiliary pilot symbol.
4. The method according to claim 3, wherein: when time-frequency
resource locations at which the first auxiliary pilot symbol, the
first primary pilot symbol, the second primary pilot symbol, and
the second auxiliary pilot symbol in the pilot symbol group are
located are
(m.sub.k,n.sub.k),(m.sub.k,n.sub.k+1),(m.sub.k,n.sub.k+2),(m.sub.k,n.sub.-
k+3); a time-frequency resource location range in which the first
primary pilot symbol is interfered with is {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+1; a time-frequency resource
location range in which the second primary pilot symbol is
interfered with is {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+2; the first auxiliary pilot
symbol and the second auxiliary pilot symbol of a transmit antenna
port j are respectively a.sub.m.sub.k,.sub.n.sub.k.sup.jand
a.sub.m.sub.k,.sub.n.sub.k+3.sup.j; a transmit value of a data
symbol at a time-frequency resource location (m, n) on the transmit
antenna port j is a.sub.m,n.sup.j; an interference coefficient
value of interference caused at the time-frequency resource
location (m, n) to the first primary pilot symbol is
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+1), wherein the time-frequency
resource location (m, n) is in the time-frequency resource location
range corresponding to the first primary pilot symbol; and an
interference coefficient value of interference caused at the
time-frequency resource location (m, n) to the second primary pilot
symbol is .zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+2), wherein the
time-frequency resource location (m, n) is in the time-frequency
resource location range corresponding to the second primary pilot
symbol, transmit values of the first auxiliary pilot symbol
a.sub.m.sub.k.sub.,n.sub.k.sup.j and the second auxiliary pilot
symbol a.sub.m.sub.k.sub.,n.sub.k+3.sup.j in the pilot symbol group
are specifically: .di-elect
cons..OMEGA..times..times..times..zeta..zeta. ##EQU00020##
.di-elect
cons..OMEGA..times..times..times..times..times..zeta..zeta.
##EQU00020.2## wherein {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+1={(m,n),
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+1.sub.).noteq.0, and
(m,n).noteq.{(m.sub.k,n.sub.k),(m.sub.k,n.sub.k+1),(m.sub.k,n.sub.k+2)}},
{hacek over (.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+2={(m,n),
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+2.sub.).noteq.0, and
(m,n).noteq.{(m.sub.k,n.sub.k+3),(m.sub.k,n.sub.k+1),(m.sub.k,
n.sub.k+2)}}.
5. A channel estimation method, comprising: for each receiving
antenna port, receiving a pilot symbol group, wherein the pilot
symbol group comprises two auxiliary pilot symbols and two primary
pilot symbols, the auxiliary pilot symbols are configured to cancel
interference caused by other data symbols to the primary pilot
symbols; obtaining receive values at time-frequency resource
locations at which primary pilot symbols from each transmit antenna
port to each receive antenna port are located, wherein the
interference caused by the other data symbols to the primary pilot
symbols is cancelled for the receive values by using the auxiliary
pilot symbols; determining a receiving sequence from each transmit
antenna port to each receive antenna port; and calculating, for
each transmit antenna port to each receive antenna port, an
estimation value of a channel between the transmit antenna port and
the receive antenna port according to the receive values of the
primary pilot symbols and the receiving sequence.
6. The method according to claim 5, wherein the determining a
receiving sequence from each transmit antenna port to each receive
antenna port comprises: obtaining an interference response matrix
for the time-frequency resource locations at which the primary
pilot symbols at a transmit end are located; obtaining a transmit
matrix that comprises transmit values of the primary pilot symbols
at the transmit end; and calculating the receiving sequence from
each transmit antenna port to each receive antenna port according
to the interference response matrix and the transmit matrix.
7. The method according to claim 6, wherein when the interference
response matrix of the transmit end is .GAMMA., the transmit matrix
of the transmit end is P, and a receiving sequence of a transmit
antenna port j is [b.sup.j.sub.0, b.sup.j.sub.1, . . . ,
b.sup.j.sub.n].sup.T, the calculating the receiving sequence of the
transmit antenna port is specifically: [b.sup.j.sub.0,
b.sup.j.sub.1, . . . ,
b.sup.j.sub.n].sup.T=.GAMMA..sup.-1P.sup.-1(0, . . . , 0, w.sub.j,
0, . . . , 0).sup.T, wherein b.sup.j.sub.n is an element in a
receiving sequence at a time-frequency resource location at which
the n.sup.th primary pilot symbol of the transmit antenna port j is
located, w.sub.j indicates pilot channel estimation gain power of
the transmit antenna port j, a quantity of 0s in (0, . . . , 0,
w.sub.j, 0, . . . , 0).sup.T is equal to n-1, w.sub.j in (0, . . .
, 0, w.sub.j, 0, . . . , 0).sup.T appears at the j.sup.th location,
and values at other locations are 0.
8. The method according to claim 6, wherein the obtaining an
interference response matrix for the time-frequency resource
locations at which the primary pilot symbols at a transmit end are
located comprises: receiving an interference response matrix
indication message sent by the transmit end; and determining,
according to the interference response matrix indication message,
the interference response matrix for the time-frequency resource
locations at which the primary pilot symbols at the transmit end
are located.
9. The method according to claim 6, wherein the obtaining an
interference response matrix for the time-frequency resource
locations at which the primary pilot symbols at a transmit end are
located comprises: determining time-frequency resource locations of
primary pilot symbols that is in a pilot symbol group and that
cause interference to the primary pilot symbols at the transmit
end; obtaining interference coefficient values of interference
caused at the determined time-frequency resource locations of the
primary pilot symbols in the pilot symbol group to the primary
pilot symbols; and constructing the interference response matrix by
using the interference coefficient values.
10. The method according to claim 5, wherein the calculating, for
each transmit antenna port to each receive antenna port, an
estimation value of a channel between the transmit antenna port and
the receive antenna port according to the receive values of the
primary pilot symbols and the receiving sequence comprises: for
each transmit antenna port to each receive antenna port,
calculating a product of row vectors that comprise the receive
values of the primary pilot symbols and column vectors that
comprise the receiving sequence of the transmit antenna port; and
calculating a ratio of the product result to pilot channel
estimation gain power of the transmit antenna port, and using the
ratio as the estimation value of the channel between the transmit
antenna port and the receive antenna port.
11. The method according to claim 10, wherein for each transmit
antenna port on each receive antenna port, when receive values of
primary pilot symbols of a receive antenna port i are separately
r.sup.i.sub.0, r.sup.i.sub.1, . . . , r.sup.i.sub.n, wherein
r.sup.i.sub.n is a receive value at a time-frequency resource
location at which the n.sup.th primary pilot symbol of the receive
antenna port i is located, and an estimation value of a channel
between the transmit antenna port j and the receive antenna port i
is H.sub.ij, the calculating an estimation value of a channel
between the transmit antenna port and the receive antenna port is
specifically: H.sub.ij=[r.sup.i.sub.0,r.sup.i.sub.1, . . .
,r.sup.i.sub.n][b.sup.j.sub.0, b.sup.j.sub.0, b.sup.j.sub.1, . . .
, b.sup.j.sub.n].sup.T/w.sub.j.
12. A sending device, comprising: a processor, at least one
transmit antenna port connected to the processor by using an
interface, and a memory connected to the processor by using a bus,
wherein the memory stores a group of program code, and the
processor is configured to invoke the program code stored in the
memory to perform the following operations: for each transmit
antenna port, inserting a pilot symbol group at four consecutive
FBMC time-frequency resource locations, wherein the pilot symbol
group comprises two auxiliary pilot symbols and two primary pilot
symbols; for each primary pilot symbol, determining a
time-frequency resource location range in which the primary pilot
symbol is interfered with; for each primary pilot symbol, obtaining
transmit values of data symbols at time-frequency resource
locations in the determined time-frequency resource location range
in which the primary pilot symbol is interfered with; for each
primary pilot symbol, obtaining, according to multiplex converter
response data, interference coefficient values of interference
caused at the time-frequency resource locations to the primary
pilot symbol, wherein the time-frequency resource locations are in
the determined time-frequency resource location range corresponding
to the primary pilot symbol; calculating a transmit value of each
auxiliary pilot symbol in the pilot symbol group according to the
obtained interference coefficient values and the obtained transmit
values of the data symbols at the time-frequency resource locations
in the time-frequency resource location range in which each primary
pilot symbol is interfered with; and sending the pilot symbol
group, wherein the pilot symbol group comprises the calculated
transmit values of the auxiliary pilot symbols.
13. The sending device according to claim 12, wherein the
inserting, by the processor, a pilot symbol group at four
consecutive FBMC time-frequency resource locations comprises:
respectively inserting a first auxiliary pilot symbol, a first
primary pilot symbol, a second primary pilot symbol, and a second
auxiliary pilot symbol at a K.sup.th, a (K+1).sup.th, a
(K+2).sup.th, and a (K+3).sup.th FBMC symbol locations on a same
subcarrier at the time-frequency resource locations, wherein K is a
natural number; or respectively inserting a first auxiliary pilot
symbol, a first primary pilot symbol, a second primary pilot
symbol, and a second auxiliary pilot symbol on a N.sup.th, a
(N+1).sup.th, a (N+2).sup.th, and a (N+3).sup.th FBMC subcarriers
at a same FBMC symbol location at the time-frequency resource
locations, wherein N is a natural number.
14. The sending device according to a claim 12, wherein the
calculating, by the processor, a transmit value of each auxiliary
pilot symbol in the pilot symbol group according to the obtained
interference coefficient values and the obtained transmit values of
the data symbols at the time-frequency resource locations in the
time-frequency resource location range in which each primary pilot
symbol is interfered with comprises: for an auxiliary pilot symbol
adjacent to the primary pilot symbol in the pilot symbol group,
adding up values obtained after separately multiplying the obtained
transmit values of the data symbols corresponding to the primary
pilot symbol by the interference coefficient values of the
interference caused at the time-frequency resource locations of the
data symbols to the primary pilot symbol, and using the calculated
added result as a first result; dividing the first result by an
interference coefficient value of interference caused at a
time-frequency resource location of the auxiliary pilot symbol to
the primary pilot symbol, and using the calculated result as a
second result; and determining a value obtained after the second
result is negated as the transmit value of the auxiliary pilot
symbol.
15. The sending device according to claim 14, wherein when
time-frequency resource locations at which the first auxiliary
pilot symbol, the first primary pilot symbol, the second primary
pilot symbol, and the second auxiliary pilot symbol in the pilot
symbol group are located are (m.sub.k,n.sub.k),(m.sub.k,n.sub.k
+1),(m.sub.k,n.sub.k+2),(m.sub.k,n.sub.k+3); a time-frequency
resource location range in which the first primary pilot symbol is
interfered with is {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+1; a time-frequency resource
location range in which the second primary pilot symbol is
interfered with is {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+2; the first auxiliary pilot
symbol and the second auxiliary pilot symbol of a transmit antenna
port j are respectively a.sub.m.sub.k.sub., n.sub.k.sup.j and
a.sub.m.sub.k.sub., n.sub.k+3.sup.j; a transmit value of a data
symbol at a time-frequency resource location (m, n) on the transmit
antenna port j is a.sub.m, n.sup.j; an interference coefficient
value of interference caused at the time-frequency resource
location (m, n) to the first primary pilot symbol is
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+1), wherein the time-frequency
resource location (m, n) is in the time-frequency resource location
range corresponding to the first primary pilot symbol; and an
interference coefficient value of interference caused at the
time-frequency resource location (m, n) to the second primary pilot
symbol is .zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+2), wherein the
time-frequency resource location (m, n) is in the time-frequency
resource location range corresponding to the second primary pilot
symbol, transmit values of the first auxiliary pilot symbol
a.sub.m.sub.k.sub.,n.sub.k.sup.j and the second auxiliary pilot
symbol a.sub.m.sub.k.sub.,n.sub.k+3.sup.j in the pilot symbol group
are specifically: .di-elect
cons..OMEGA..times..times..times..zeta..zeta. ##EQU00021##
.di-elect cons..OMEGA..times..times..times..times..zeta..zeta.
##EQU00021.2## wherein {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+1={(m,n),.zeta..sub.(m-m.sub.k.sub.,n--
n.sub.k+1.sub.).noteq.0, and
(m,n).noteq.{(m.sub.k,n.sub.k),(m.sub.k,n.sub.k+1),(m.sub.k,n.sub.k+2)}},
{hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+2={(m,n),.zeta..sub.(m-m.sub.k.sub.,n--
n.sub.k+2.sub.).noteq.0, and
(m,n).noteq.{(m.sub.k,n.sub.k+3),(m.sub.k,n.sub.k+1),(m.sub.k,n.sub.k+2)}-
}.
16. A receiving device, comprising: a processor, at least one
receive antenna port connected to the processor by using an
interface, and a memory connected to the processor by using a bus,
wherein the memory stores a group of program code, and the
processor is configured to invoke the program code stored in the
memory to perform the following operations: for each receiving
antenna port, receiving a pilot symbol group, wherein the pilot
symbol group comprises two auxiliary pilot symbols and two primary
pilot symbols, the auxiliary pilot symbols are configured to cancel
interference caused by other data symbols to the primary pilot
symbols; obtaining receive values at time-frequency resource
locations at which primary pilot symbols sent from each transmit
antenna port to each receive antenna port are located, wherein the
interference caused by the other data symbols to the primary pilot
symbols is cancelled for the receive values by using the auxiliary
pilot symbols; determining a receiving sequence from each transmit
antenna port to each receive antenna port; and calculating, for
each transmit antenna port to each receive antenna port, an
estimation value of a channel between the transmit antenna port and
the receive antenna port according to the receive values of the
primary pilot symbols and the receiving sequence.
17. The receiving device according to claim 16, wherein the
determining, by the processor, a receiving sequence from each
transmit antenna port to each receive antenna port comprises:
obtaining an interference response matrix for the time-frequency
resource locations at which the primary pilot symbols at a transmit
end are located; obtaining a transmit matrix that comprises
transmit values of the primary pilot symbols at the transmit end;
and calculating the receiving sequence from each transmit antenna
port to each receive antenna port according to the interference
response matrix and the transmit matrix.
18. The receiving device according to claim 17, wherein when the
interference response matrix of the transmit end is .GAMMA., the
transmit matrix of the transmit end is P, and a receiving sequence
of a transmit antenna port j is [b.sup.j.sub.0, b.sup.j.sub.1, . .
. , b.sup.j.sub.n].sup.T, the calculating, by the processor, the
receiving sequence of the transmit antenna port is specifically:
[b.sup.j.sub.0, b.sup.j.sub.1, . . . , b.sup.j
.sub.n].sup.T=.GAMMA..sup.-1P.sup.-1(0 , . . . , 0, w.sub.j, 0, . .
. , 0).sup.T, wherein bin is an element in a receiving sequence at
a time-frequency resource location at which the n.sup.th primary
pilot symbol of the transmit antenna port j is located, w.sub.j
indicates pilot channel estimation gain power of the transmit
antenna port j, a quantity of 0s in (0, . . . , 0, w.sub.j, 0 , . .
. , 0).sup.T is equal to n-1, w.sub.j in (0, . . . , 0, w.sub.j, 0.
. . , 0).sup.T appears at the j.sup.th location, and values at
other locations are 0.
19. The receiving device according to claim 17, wherein the
obtaining, by the processor, an interference response matrix for
the time-frequency resource locations at which the primary pilot
symbols at a transmit end are located comprises: receiving an
interference response matrix indication message sent by the
transmit end; and determining the interference response matrix for
the time-frequency resource locations of the primary pilot symbols
at the transmit end according to the interference response matrix
indication message.
20. The receiving device according to claim 17, wherein the
obtaining, by the processor, an interference response matrix for
the time-frequency resource locations at which the primary pilot
symbols at a transmit end are located comprises: determining
time-frequency resource locations of primary pilot symbols that is
in a pilot symbol group and that cause interference to the primary
pilot symbols at the transmit end; obtaining interference
coefficient values of interference caused at the determined
time-frequency resource locations of the primary pilot symbols in
the pilot symbol group to the primary pilot symbols; and
constructing the interference response matrix by using the
interference coefficient values.
21. The receiving device according to claim 16, wherein the
calculating, by the processor for each transmit antenna port to
each receive antenna port, an estimation value of a channel between
the transmit antenna port and the receive antenna port according to
the receive values of the primary pilot symbols and the receiving
sequence comprises: for each transmit antenna port to each receive
antenna port, calculating a product of row vectors that comprise
the receive values of the primary pilot symbols and column vectors
that comprise the receiving sequence of the transmit antenna port;
and calculating a ratio of the product result to pilot channel
estimation gain power of the transmit antenna port, and using the
ratio as the estimation value of the channel between the transmit
antenna port and the receive antenna port.
22. The receiving device according to claim 21, wherein for each
transmit antenna port on each receive antenna port, when receive
values of primary pilot symbols of a receive antenna port i are
separately r.sup.i .sub.0, r.sup.i .sub.1, . . ., r.sup.i.sub.n,
wherein r.sup.i.sub.n is a receive value at a time-frequency
resource location at which the n.sup.th primary pilot symbol of the
receive antenna port i is located, and an estimation value of a
channel between the transmit antenna port j and the receive antenna
port i is H.sub.ij, the calculating, by the processor, an
estimation value of a channel between the transmit antenna port and
the receive antenna port is specifically:
H.sub.ij=[r.sup.i.sub.0,r.sup.i.sub.1, . . .
,r.sup.i.sub.n][b.sup.j.sub.0,b.sup.j.sub.1, . . .
,b.sup.j.sub.n].sup.T/w.sub.j.
Description
TECHNICAL FIELD
The present disclosure relates to the field of communications
technologies, and in particular, to an FBMC-based pilot sending
method, a channel estimation method, and a related apparatus.
BACKGROUND
A filter bank multicarrier (FBMC) technology is referred to as one
of candidate technologies of next generation mobile communication.
Compared with a current commonly used multicarrier technology, such
as a cyclic prefix-orthogonal frequency division multiplexing
(CP-OFDM) technology, the FBMC technology has advantages such as a
desirable outband suppression effect, high frequency spectrum
utilization, and flexible use of a frequency spectrum. Multi-input
multi-output (MIMO) is a technology in which multiple transmit
antennas or receive antennas are used to increase a system
throughput and a transmission distance, and is a mandatory
technology in a current wireless communications system. In the
wireless communications system, to resist impact of a radio channel
on transmitted data, a receive end needs to perform channel
estimation, for example, perform channel estimation in an OFDM
system by using an orthogonal pilot. However, the FBMC system has
inherent interference, and consequently, a sent pilot symbol is
polluted at the receive end. Therefore, both design of a pilot
sending algorithm and a channel estimation algorithm directly
affect final channel estimation performance.
There are mainly two existing MIMO-FBMC pilot sending methods: an
interference approximation method (IAM) and an auxiliary pilot
method (APM). However, the IAM method has disadvantages of high
pilot overheads and low spectral efficiency. Compared with the IAM
method, the APM method has low pilot overheads, but an auxiliary
pilot causes a power increase, and especially in an MIMO case, the
power increase is severer.
SUMMARY
Embodiments of the present disclosure disclose an FBMC-based pilot
sending method, a channel estimation method, and a related
apparatus, so as to reduce pilot overheads and a power increase
caused by an auxiliary pilot, and improve channel estimation
performance.
A first aspect of the embodiments of the present disclosure
discloses an FBMC-based pilot sending method, including:
for each transmit antenna port, inserting a pilot symbol group at
four consecutive FBMC time-frequency resource locations, where the
pilot symbol group includes two auxiliary pilot symbols and two
primary pilot symbols;
for each primary pilot symbol, determining a time-frequency
resource location range in which the primary pilot symbol is
interfered with;
for each primary pilot symbol, obtaining transmit values of data
symbols at time-frequency resource locations in the determined
time-frequency resource location range in which the primary pilot
symbol is interfered with;
for each primary pilot symbol, obtaining, according to multiplex
converter response data, interference coefficient values of
interference caused at the time-frequency resource locations to the
primary pilot symbol, where the time-frequency resource locations
are in the determined time-frequency resource location range
corresponding to the primary pilot symbol;
calculating a transmit value of each auxiliary pilot symbol in the
pilot symbol group according to the obtained interference
coefficient values and the obtained transmit values of the data
symbols at the time-frequency resource locations at which each
primary pilot symbol is interfered with; and
sending the pilot symbol group, where the pilot symbol group
includes the calculated transmit values of the auxiliary pilot
symbols.
In a first possible implementation manner of the first aspect of
the embodiments of the present disclosure, the inserting a pilot
symbol group at four consecutive FBMC time-frequency resource
locations includes:
respectively inserting a first auxiliary pilot symbol, a first
primary pilot symbol, a second primary pilot symbol, and a second
auxiliary pilot symbol at a K.sup.th, a (K+1).sup.th, a
(K+2).sup.th, and a (K+3).sup.th FBMC symbol locations on a same
subcarrier at the time-frequency resource locations, where K is a
natural number; or respectively inserting a first auxiliary pilot
symbol, a first primary pilot symbol, a second primary pilot
symbol, and a second auxiliary pilot symbol on a N.sup.th, a
(N+1).sup.th, a (N+2).sup.th, and a (N+3).sup.th FBMC subcarriers
at a same FBMC symbol location at the time-frequency resource
locations, where N is a natural number.
With reference to an implementation manner of the first aspect of
the embodiments of the present disclosure or the first possible
implementation manner of the first aspect of the embodiments of the
present disclosure, in a second possible implementation manner of
the first aspect of the embodiments of the present disclosure, the
determining a time-frequency resource location range in which the
primary pilot symbol is interfered with includes:
for each primary pilot symbol in the pilot symbol group,
determining, according to the multiplex converter response data and
a time-frequency resource location of the primary pilot symbol, the
time-frequency resource location range in which the primary pilot
symbol is interfered with.
With reference to the implementation manner of the first aspect of
the present disclosure or the first possible implementation manner
of the first aspect of the present disclosure, in a third possible
implementation manner of the first aspect of the embodiments of the
present disclosure, the determining a time-frequency resource
location range in which the primary pilot symbol is interfered with
includes:
obtaining a preset time-frequency resource location range in which
the primary pilot symbol is interfered with.
With reference to the implementation manner of the first aspect of
the present disclosure or the first possible implementation manner
of the first aspect of the present disclosure, in a fourth possible
implementation manner of the first aspect of the embodiments of the
present disclosure, the determining a time-frequency resource
location range in which the primary pilot symbol is interfered with
includes:
determining, based on an interference estimation algorithm, the
time-frequency resource location range in which the primary pilot
symbol is interfered with.
With reference to any one of the implementation manner of the first
aspect of the present disclosure or the first to the fourth
possible implementation manners of the first aspect of the present
disclosure, in a fifth possible implementation manner of the first
aspect of the embodiments of the present disclosure, the
calculating a transmit value of each auxiliary pilot symbol in the
pilot symbol group according to the obtained interference
coefficient values and the obtained transmit values of the data
symbols at the time-frequency resource locations in the
time-frequency resource location range in which each primary pilot
symbol is interfered with includes:
for an auxiliary pilot symbol adjacent to the primary pilot symbol
in the pilot symbol group, adding up values obtained after
separately multiplying the obtained transmit values of the data
symbols corresponding to the primary pilot symbol by the
interference coefficient values of the interference caused at the
time-frequency resource locations of the data symbols to the
primary pilot symbol, and using the calculated added result as a
first result;
dividing the first result by an interference coefficient value of
interference caused at a time-frequency resource location of the
auxiliary pilot symbol to the primary pilot symbol, and using the
calculated result as a second result; and
determining a value obtained after the second result is negated as
the transmit value of the auxiliary pilot symbol.
In a sixth possible implementation manner of the first aspect of
the embodiments of the present disclosure, when time-frequency
resource locations at which the first auxiliary pilot symbol, the
first primary pilot symbol, the second primary pilot symbol, and
the second auxiliary pilot symbol in the pilot symbol group are
located are
(m.sub.k,n.sub.k),(m.sub.k,n.sub.k+1),(m.sub.k,n.sub.k+2),(m.sub.k,n.sub.-
k+3); a time-frequency resource location range in which the first
primary pilot symbol is interfered with is {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+1; a time-frequency resource
location range in which the second primary pilot symbol is
interfered with is {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+2; the first auxiliary pilot
symbol and the second auxiliary pilot symbol of a transmit antenna
port j are respectively a.sub.m.sub.k.sub.,n.sub.k.sup.j and
a.sub.m.sub.k.sub.,n.sub.k+3.sup.j; a transmit value of a data
symbol at a time-frequency resource location (m, n) on the transmit
antenna port j is a.sub.m,n.sup.j; an interference coefficient
value of interference caused at the time-frequency resource
location (m, n) to the first primary pilot symbol is
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+1), where the time-frequency
resource location (m, n) is in the time-frequency resource location
range corresponding to the first primary pilot symbol; and an
interference coefficient value of interference caused at the
time-frequency resource location (m, n) to the second primary pilot
symbol is .zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+2), where the
time-frequency resource location (m, n) is in the time-frequency
resource location range corresponding to the second primary pilot
symbol, transmit values of the first auxiliary pilot symbol
a.sub.m.sub.k.sub.,n.sub.k.sup.j and the second auxiliary pilot
symbol a.sub.m.sub.k.sub.,n.sub.k+3.sup.j in the pilot symbol group
are specifically:
.di-elect cons..OMEGA..times..times..times..zeta..zeta.
##EQU00001## .di-elect
cons..OMEGA..times..times..times..times..times..zeta..zeta.
##EQU00001.2##
where
{hacek over (.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+1={(m,n),
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+1.sub.).noteq.0, and
(m,n).noteq.{(m.sub.k,n.sub.k),(m.sub.k,n.sub.k+1),(m.sub.k,n.sub.k+2)}},
{hacek over (.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+2={(m,n),
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+2.sub.).noteq.0, and
(m,n).noteq.{(m.sub.k,n.sub.k+3),(m.sub.k,n.sub.k+1),(m.sub.k,
n.sub.k+2)}}.
With reference to any one of the first aspect of the embodiments of
the present disclosure or the first to the sixth possible
implementation manners of the first aspect of the embodiments of
the present disclosure, in a seventh possible implementation manner
of the first aspect of the embodiments of the present disclosure,
primary pilot symbols on different transmit antenna ports are sent
in a code division manner.
A second aspect of the embodiments of the present disclosure
discloses a channel estimation method, including:
obtaining receive values at time-frequency resource locations at
which primary pilot symbols sent from each transmit antenna port to
each receive antenna port are located, where interference caused by
other data symbols to the primary pilot symbols is cancelled for
the receive values by using auxiliary pilot symbols;
determining a receiving sequence from each transmit antenna port to
each receive antenna port; and
calculating, for each transmit antenna port to each receive antenna
port, an estimation value of a channel between the transmit antenna
port and the receive antenna port according to the receive values
of the primary pilot symbols and the receiving sequence.
In a first possible implementation manner of the second aspect of
the embodiments of the present disclosure, the determining a
receiving sequence from each transmit antenna port to each receive
antenna port includes:
obtaining an interference response matrix for the time-frequency
resource locations at which the primary pilot symbols at a transmit
end are located;
obtaining a transmit matrix that includes transmit values of
primary pilot symbols at the transmit end; and
calculating the receiving sequence from each transmit antenna port
to each receive antenna port according to the interference response
matrix and the transmit matrix.
With reference to the first possible implementation manner of the
second aspect of the embodiments of the present disclosure, in a
second possible implementation manner of the second aspect of the
embodiments of the present disclosure, when the interference
response matrix of the transmit end is .GAMMA., the transmit matrix
of the transmit end is P, and a receiving sequence of a transmit
antenna port j is [b.sup.j.sub.0, b.sup.j.sub.1, . . . ,
b.sup.j.sub.n].sup.T, the calculating the receiving sequence of the
transmit antenna port is specifically:
[b.sup.j.sub.0, b.sup.j.sub.1, . . . ,
b.sup.j.sub.n].sup.T=.GAMMA..sup.-1P.sup.-1 (0, . . . , 0, w.sub.j,
0, . . . , 0).sup.T, where b.sup.j.sub.n is a receiving sequence at
a time-frequency resource location at which the n.sup.th primary
pilot symbol of the transmit antenna port j is located, w.sub.j
indicates pilot channel estimation gain power of the transmit
antenna port j, a quantity of 0s in (0, . . . , 0, w.sub.j, 0, . .
. , 0).sup.T is equal to n-1, w.sub.j in (0, . . . , 0, w.sub.j, 0,
. . . , 0).sup.T appears at the j.sup.th location, and values at
other locations are 0.
In a third possible implementation manner of the second aspect of
the embodiments of the present, the calculating, for each transmit
antenna port to each receive antenna port, an estimation value of a
channel between the transmit antenna port and the receive antenna
port according to the receive values of the primary pilot symbols
and the receiving sequence includes:
for each transmit antenna port to each receive antenna port,
calculating a product of row vectors that include the receive
values of the primary pilot symbols and column vectors that include
the receiving sequence of the transmit antenna port; and
calculating a ratio of the product result to pilot channel
estimation gain power of the transmit antenna port, and using the
ratio as the estimation value of the channel between the transmit
antenna port and the receive antenna port.
With reference to the third possible implementation manner of the
second aspect of the embodiments of the present disclosure, in a
fourth possible implementation manner of the second aspect of the
embodiments of the present disclosure, for each transmit antenna
port on each receive antenna port, when receive values of primary
pilot symbols of a receive antenna port i are separately
r.sup.i.sub.0, r.sup.i.sub.1, . . . , r.sup.i.sub.n, where
r.sup.i.sub.n is a receive value at a time-frequency resource
location at which the n.sup.th primary pilot symbol of the receive
antenna port i is located, and an estimation value of a channel
between the transmit antenna port j and the receive antenna port i
is H.sub.ij, the calculating an estimation value of a channel
between the transmit antenna port and the receive antenna port is
specifically: H.sub.ij=[r.sup.i.sub.0,r.sup.i.sub.1, . . .
,r.sup.i.sub.n][b.sup.j.sub.0,b.sup.j.sub.1, . . .
,b.sup.j.sub.n].sup.T/w.sub.j.
With reference to the first possible implementation manner of the
second aspect of the embodiments of the present disclosure, in a
fifth possible implementation manner of the second aspect of the
embodiments of the present disclosure, the obtaining an
interference response matrix for the time-frequency resource
locations at which the primary pilot symbols at a transmit end are
located includes:
receiving an interference response matrix indication message sent
by the transmit end; and
determining, according to the interference response matrix
indication message, the interference response matrix for the
time-frequency resource locations at which the primary pilot
symbols at the transmit end are located.
With reference to the first possible implementation manner of the
second aspect of the embodiments of the present disclosure, in a
sixth possible implementation manner of the second aspect of the
embodiments of the present disclosure, the obtaining an
interference response matrix for the time-frequency resource
locations at which the primary pilot symbols at a transmit end are
located includes:
determining time-frequency resource locations, in a pilot symbol
group, at which the primary pilot symbols at the transmit end are
interfered with;
obtaining interference coefficient values of interference caused at
the determined time-frequency resource locations in the pilot
symbol group to the primary pilot symbols; and
constructing the interference response matrix by using the
interference coefficient values.
With reference to the sixth possible implementation manner of the
second aspect of the embodiments of the present disclosure, in a
seventh possible implementation manner of the second aspect of the
embodiments of the present disclosure, the determining
time-frequency resource locations, in a pilot symbol group, at
which the primary pilot symbols at the transmit end are interfered
with includes:
for each primary pilot symbol in the pilot symbol group,
determining, according to multiplex converter response data and a
time-frequency resource location of the primary pilot symbol, the
time-frequency resource location at which the primary pilot symbol
is interfered with.
With reference to the sixth possible implementation manner of the
second aspect of the embodiments of the present disclosure, in an
eighth possible implementation manner of the second aspect of the
embodiments of the present disclosure, the determining
time-frequency resource locations, in a pilot symbol group, at
which the primary pilot symbols at the transmit end are interfered
with includes:
obtaining preset time-frequency resource locations, in the pilot
symbol group, at which the primary pilot symbols are interfered
with.
With reference to the sixth possible implementation manner of the
second aspect of the embodiments of the present disclosure, in a
ninth possible implementation manner of the second aspect of the
embodiments of the present disclosure, the determining
time-frequency resource locations, in a pilot symbol group, at
which the primary pilot symbols at the transmit end are interfered
with includes:
receiving an interference indication message sent by the transmit
end; and
determining, according to the interference indication message, the
time-frequency resource locations, in the pilot symbol group, at
which the primary pilot symbols at the transmit end are interfered
with.
With reference to the sixth possible implementation manner of the
second aspect of the embodiments of the present disclosure, in a
tenth possible implementation manner of the second aspect of the
embodiments of the present disclosure, the obtaining interference
coefficient values of interference caused at the determined
time-frequency resource locations in the pilot symbol group to the
primary pilot symbols includes:
obtaining, according to multiplex converter response data, the
interference coefficient values of the interference caused at the
time-frequency resource locations to the primary pilot symbols,
where the time-frequency resource locations are in the determined
time-frequency resource location range corresponding to the primary
pilot symbols.
With reference to the sixth possible implementation manner of the
second aspect of the embodiments of the present disclosure, in an
eleventh possible implementation manner of the second aspect of the
embodiments of the present disclosure, the obtaining interference
coefficient values of interference caused at the determined
time-frequency resource locations in the pilot symbol group to the
primary pilot symbols includes:
receiving an interference coefficient table indication message sent
by the transmit end; and
obtaining the interference coefficient values, in the interference
coefficient table indication message, of the interference caused at
the determined time-frequency resource locations to the primary
pilot symbols.
With reference to any one of the second aspect of the embodiments
of the present disclosure or the first to the eleventh possible
implementation manners of the second aspect of the embodiments of
the present disclosure, in a twelfth possible implementation manner
of the second aspect of the embodiments of the present disclosure,
primary pilot symbols that are on different transmit antenna ports
are sent by the transmit end are distinguished in a code division
manner.
A third aspect of the embodiments of the present disclosure
discloses an FBMC-based pilot sending apparatus, including:
a pilot inserting unit, configured to: for each transmit antenna
port, insert a pilot symbol group at four consecutive FBMC
time-frequency resource locations, where the pilot symbol group
includes two auxiliary pilot symbols and two primary pilot
symbols;
a first determining unit, configured to: for each primary pilot
symbol inserted by the pilot inserting unit, determine a
time-frequency resource location range in which the primary pilot
symbol is interfered with;
a first obtaining unit, configured to: for each primary pilot
symbol, obtain transmit values of data symbols at time-frequency
resource locations in the time-frequency resource location range
that is determined by the first determining unit and in which the
primary pilot symbol is interfered with;
a second obtaining unit, configured to: for each primary pilot
symbol, obtain, according to multiplex converter response data,
interference coefficient values of interference caused at the
time-frequency resource locations to the primary pilot symbol,
where the time-frequency resource locations are in the
time-frequency resource location range that is determined by the
first determining unit and that is corresponding to the primary
pilot symbol;
a calculation unit, configured to: calculate a transmit value of
each auxiliary pilot symbol in the pilot symbol group according to
the interference coefficient values obtained by the second
obtaining unit and the transmit values that are obtained by the
first obtaining unit and are of the data symbols at the
time-frequency resource locations in the time-frequency resource
location range in which each primary pilot symbol is interfered
with; and
a sending unit, configured to send the pilot symbol group, where
the pilot symbol group includes the calculated transmit values of
the auxiliary pilot symbols.
In a first possible implementation manner of the third aspect of
the embodiments of the present disclosure, the pilot inserting unit
is specifically configured to respectively insert a first auxiliary
pilot symbol, a first primary pilot symbol, a second primary pilot
symbol, and a second auxiliary pilot symbol at a K.sup.th, a
(K+1).sup.th, a (K+2).sup.th, and a (K+3).sup.th FBMC symbol
locations on a same subcarrier at the time-frequency resource
locations, where K is a natural number; or respectively insert a
first auxiliary pilot symbol, a first primary pilot symbol, a
second primary pilot symbol, and a second auxiliary pilot symbol on
a N.sup.th, a (N+1).sup.th, a (N+2).sup.th, and a (N+3).sup.th FBMC
subcarriers at a same FBMC symbol location at the time-frequency
resource locations, where N is a natural number.
With reference to an implementation manner of the third aspect of
the embodiments of the present disclosure or the first possible
implementation manner of the third aspect of the embodiments of the
present disclosure, in a second possible implementation manner of
the third aspect of the embodiments of the present disclosure, the
first determining unit is specifically configured to: for each
primary pilot symbol in the pilot symbol group inserted by the
pilot inserting unit, determine, according to the multiplex
converter response data and a time-frequency resource location of
the primary pilot symbol, the time-frequency resource location
range in which the primary pilot symbol is interfered with.
In a third possible implementation manner of the third aspect of
the embodiments of the present disclosure, the first determining
unit is specifically configured to obtain a preset time-frequency
resource location range in which the primary pilot symbol in the
pilot symbol group inserted by the pilot inserting unit is
interfered with.
In a fourth possible implementation manner of the third aspect of
the embodiments of the present disclosure, the first determining
unit is specifically configured to determine, based on an
interference estimation algorithm, the time-frequency resource
location range in which the primary pilot symbol in the pilot
symbol group inserted by the pilot inserting unit is interfered
with.
With reference to any one of the implementation manner of the third
aspect of the embodiments of the present disclosure or the first to
the fourth possible implementation manners of the third aspect of
the embodiments of the present disclosure, in a fifth possible
implementation manner of the third aspect of the embodiments of the
present disclosure, the calculation unit includes:
a first calculation unit, configured to: for an auxiliary pilot
symbol adjacent to the primary pilot symbol in the pilot symbol
group, add up values obtained after separately multiplying the
obtained transmit values of the data symbols corresponding to the
primary pilot symbol by the interference coefficient values of the
interference caused at the time-frequency resource locations of the
data symbols to the primary pilot symbol, and use the calculated
added result as a first result;
a second calculation unit, configured to: divide the first result
calculated by the first calculation unit by an interference
coefficient value of interference caused at a time-frequency
resource location of the auxiliary pilot symbol to the primary
pilot symbol, and use the calculated result as a second result;
and
a second determining unit, configured to determine a value obtained
after the second result calculated by the second calculation unit
is negated as the transmit value of the auxiliary pilot symbol.
With reference to the fifth possible implementation manner of the
third aspect of the embodiments of the present disclosure, in a
sixth possible implementation manner of the third aspect of the
embodiments of the present disclosure, when time-frequency resource
locations at which the first auxiliary pilot symbol, the first
primary pilot symbol, the second primary pilot symbol, and the
second auxiliary pilot symbol in the pilot symbol group are located
are
(m.sub.k,n.sub.k),(m.sub.k,n.sub.k+1),(m.sub.k,n.sub.k+2),(m.sub.k,n.sub.-
k+3); a time-frequency resource location range in which the first
primary pilot symbol is interfered with is {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+1; a time-frequency resource
location range in which the second primary pilot symbol is
interfered with is {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+2; the first auxiliary pilot
symbol and the second auxiliary pilot symbol of a transmit antenna
port j are respectively a.sub.m.sub.k.sub.,n.sub.k.sup.j and
a.sub.m.sub.k.sub.,n.sub.k+3.sup.j; a transmit value of a data
symbol at a time-frequency resource location (m, n) on the transmit
antenna port j is a.sub.m,n.sup.j; an interference coefficient
value of interference caused at the time-frequency resource
location (m, n) to the first primary pilot symbol is
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+1.sub.), where the
time-frequency resource location (m, n) is in the time-frequency
resource location range corresponding to the first primary pilot
symbol; and an interference coefficient value of interference
caused at the time-frequency resource location (m, n) to the second
primary pilot symbol is
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+2.sub.), where the
time-frequency resource location (m, n) is in the time-frequency
resource location range corresponding to the second primary pilot
symbol, transmit values, calculated by the calculation unit, of the
first auxiliary pilot symbol a.sub.m.sub.k.sub.,n.sub.k.sup.j and
the second auxiliary pilot symbol
a.sub.m.sub.k.sub.,n.sub.k+3.sup.j are:
.di-elect cons..OMEGA..times..times..times..zeta..zeta.
##EQU00002## .di-elect
cons..OMEGA..times..times..times..times..times..zeta..zeta.
##EQU00002.2##
where
{hacek over (.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+1={(m,n),
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+1.sub.).noteq.0, and
(m,n).noteq.{(m.sub.k,n.sub.k),(m.sub.k,n.sub.k+1),(m.sub.k,
n.sub.k+2)}},
{hacek over (.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+2={(m,n),
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+2.sub.).noteq.0, and
(m,n).noteq.{(m.sub.k,n.sub.k+3),(m.sub.k,n.sub.k+1),(m.sub.k,n.sub.k+2)}-
},
With reference to any one of the third aspect of the embodiments of
the present disclosure or the first to the sixth possible
implementation manners of the third aspect of the embodiments of
the present disclosure, in a seventh possible implementation manner
of the third aspect of the embodiments of the present disclosure,
the sending unit sends primary pilot symbols on different transmit
antenna ports in a code division manner.
A fourth aspect of the embodiments of the present disclosure
discloses a channel estimation apparatus, including:
an obtaining unit, configured to obtain receive values at
time-frequency resource locations at which primary pilot symbols
sent from each transmit antenna port to each receive antenna port
are located, where interference caused by other data symbols to the
primary pilot symbols is cancelled for the receive values by using
auxiliary pilot symbols;
a determining unit, configured to determine a receiving sequence
from each transmit antenna port to each receive antenna port;
and
a calculation unit, configured to: for each transmit antenna port
to each receive antenna port, calculate an estimation value of a
channel between the transmit antenna port and the receive antenna
port according to the receive values obtained by the obtaining unit
that are of the primary pilot symbols and the receiving sequence
determined by the determining unit.
In a first possible implementation manner of the fourth aspect, the
determining unit includes:
a first obtaining unit, configured to obtain an interference
response matrix for the time-frequency resource locations at which
the primary pilot symbols at a transmit end are located;
a second obtaining unit, configured to obtain a transmit matrix
that includes transmit values of primary pilot symbols at the
transmit end; and
a first calculation unit, configured to calculate the receiving
sequence from each transmit antenna port to each receive antenna
port according to the interference response matrix and the transmit
matrix.
With reference to the first possible implementation manner of the
fourth aspect of the embodiments of the present disclosure, in a
second possible implementation manner of the fourth aspect of the
embodiments of the present disclosure, when the interference
response matrix of the transmit end is .GAMMA., the transmit matrix
of the transmit end is P, and a receiving sequence of a transmit
antenna port j is [b.sup.j.sub.0, b.sup.j.sub.1, . . . ,
b.sup.j.sub.n].sup.T, that the first calculation unit calculates
the receiving sequence of the transmit antenna port is
specifically:
[b.sup.j.sub.0, b.sup.j.sub.1, . . . ,
b.sup.j.sub.n].sup.T=.GAMMA..sup.-1P.sup.-1 (0, . . . , 0, w.sub.j,
0, . . . , 0).sup.T, where b.sup.j.sub.n is a receiving sequence at
a time-frequency resource location at which the n.sup.th primary
pilot symbol of the transmit antenna port j is located, w.sub.j
indicates pilot channel estimation gain power of the transmit
antenna port j, a quantity of 0s in (0, . . . , 0, w.sub.j, 0, . .
. , 0).sup.T is equal to n-1, w.sub.j in (0, . . . , 0, w.sub.j, 0,
. . . , 0).sup.T appears at the j.sup.th location, and values at
other locations are 0.
In a third possible implementation manner of the fourth aspect of
the embodiments of the present disclosure, the calculation unit
includes:
a third calculation unit, configured to: for each transmit antenna
port to each receive antenna port, calculate a product of row
vectors that include the receive values obtained by the obtaining
unit that are of the primary pilot symbols and column vectors that
include the receiving sequence that is determined by the
determining unit and is of the transmit antenna port; and
a fourth calculation unit, configured to: calculate a ratio of a
result calculated by the third calculation unit to pilot channel
estimation gain power of the transmit antenna port, and use the
ratio as the estimation value of the channel between the transmit
antenna port and the receive antenna port.
With reference to the third possible implementation manner of the
fourth aspect of the embodiments of the present disclosure, in a
fourth possible implementation manner of the fourth aspect of the
embodiments of the present disclosure, for each transmit antenna
port on each receive antenna port, when receive values of primary
pilot symbols of a receive antenna port i are separately
r.sup.i.sub.0, r.sup.i.sub.1, . . . , r.sup.i.sub.n, where
r.sup.i.sub.n is a receive value at a time-frequency resource
location at which the n.sup.th primary pilot symbol of the receive
antenna port i is located, and an estimation value of a channel
between the transmit antenna port j and the receive antenna port i
is H.sub.ij, that the calculation unit calculates an estimation
value of a channel between the transmit antenna port and the
receive antenna port is specifically: H.sub.ij=[r.sup.i.sub.0,
r.sup.i.sub.1, . . . , r.sup.i.sub.n][b.sup.j.sub.0, b.sup.j.sub.1,
. . . , b.sup.j.sub.n].sup.T/w.sub.j.
With reference to the first possible implementation manner of the
fourth aspect of embodiments of the present disclosure, in a fifth
possible implementation manner of the fourth aspect of the
embodiments of the present disclosure, the first obtaining unit
includes:
a first receiving unit, configured to receive an interference
response matrix indication message sent by the transmit end;
and
a first determining unit, configured to determine the interference
response matrix for the time-frequency resource locations of the
primary pilot symbols at the transmit end according to the
interference response matrix indication message.
With reference to the first possible implementation manner of the
fourth aspect of embodiments of the present disclosure, in a sixth
possible implementation manner of the fourth aspect of the
embodiments of the present disclosure, the first obtaining unit
includes:
a second determining unit, configured to determine time-frequency
resource locations, in a pilot symbol group, at which the primary
pilot symbols at the transmit end are interfered with; and
a second obtaining unit, configured to: obtain interference
coefficient values of interference caused at the determined
time-frequency resource locations in the pilot symbol group to the
primary pilot symbols, and construct the interference response
matrix by using the interference coefficient values.
With reference to the sixth possible implementation manner of the
fourth aspect of the embodiments of the present disclosure, in a
seventh possible implementation manner of the fourth aspect of the
embodiments of the present disclosure, the second determining unit
is specifically configured to: for each primary pilot symbol in the
pilot symbol group, determine, according to multiplex converter
response data and a time-frequency resource location of the primary
pilot symbol, the time-frequency resource location at which the
primary pilot symbol is interfered with.
With reference to the sixth possible implementation manner of the
fourth aspect of the embodiments of the present disclosure, in an
eighth possible implementation manner of the fourth aspect of the
embodiments of the present disclosure, the second determining unit
is specifically configured to obtain preset time-frequency resource
locations, in the pilot symbol group, at which the primary pilot
symbols are interfered with.
With reference to the sixth possible implementation manner of the
fourth aspect of embodiments of the present disclosure, in a ninth
possible implementation manner of the fourth aspect of the
embodiments of the present disclosure, the second determining unit
includes:
a second receiving unit, configured to receive an interference
indication message sent by the transmit end; and
a third determining unit, configured to determine the
time-frequency resource locations, in the pilot symbol group, at
which the primary pilot symbols at the transmit end are interfered
with.
With reference to the sixth possible implementation manner of the
fourth aspect of the embodiments of the present disclosure, in a
tenth possible implementation manner of the fourth aspect of the
embodiments of the present disclosure, the second obtaining unit is
specifically configured to: obtain, according to multiplex
converter response data, the interference coefficient values of the
interference caused at the time-frequency resource locations
determined by the second determining unit to the primary pilot
symbols; and construct the interference response matrix by using
the interference coefficient values.
With reference to the sixth possible implementation manner of the
fourth aspect of embodiments of the present disclosure, in an
eleventh possible implementation manner of the fourth aspect of the
embodiments of the present disclosure, the second obtaining unit
includes:
a third receiving unit, configured to receive an interference
coefficient table indication message sent by the transmit end;
and
a third obtaining unit, configured to: obtain the interference
coefficient values, in the interference coefficient table
indication message, of the interference caused at the determined
time-frequency resource locations to the primary pilot symbols; and
construct the interference response matrix by using the
interference coefficient values.
With reference to any one of the fourth aspect of the embodiments
of the present disclosure or the first to the eleventh possible
implementation manners of the fourth aspect of the embodiments of
the present disclosure, in a twelfth possible implementation manner
of the fourth aspect of the embodiments of the present disclosure,
primary pilot symbols that are on different transmit antenna ports
are sent by the transmit end are distinguished in a code division
manner.
A fifth aspect of the embodiments of the present disclosure
discloses a computer storage medium, where the computer storage
medium stores a program, and when the program is performed, all or
some steps of the FBMC-based pilot sending method disclosed in the
first aspect of the embodiments of the present disclosure are
included.
A sixth aspect of the embodiments of the present disclosure
discloses a computer storage medium, where the computer storage
medium stores a program, and when the program is performed, all or
some steps of the channel estimation method disclosed in the second
aspect of the embodiments of the present disclosure are
included.
A seventh aspect of the embodiments of the present disclosure
discloses a sending device, including: a processor, at least one
transmit antenna port connected to the processor by using an
interface, and a memory connected to the processor by using a bus,
where the memory stores a group of program code, and the processor
is configured to invoke the program code stored in the memory to
perform the following operations:
for each transmit antenna port, inserting a pilot symbol group at
four consecutive FBMC time-frequency resource locations, where the
pilot symbol group includes two auxiliary pilot symbols and two
primary pilot symbols;
for each primary pilot symbol, determining a time-frequency
resource location range in which the primary pilot symbol is
interfered with;
for each primary pilot symbol, obtaining transmit values of data
symbols at time-frequency resource locations in the determined
time-frequency resource location range in which the primary pilot
symbol is interfered with;
for each primary pilot symbol, obtaining, according to multiplex
converter response data, interference coefficient values of
interference caused at the time-frequency resource locations to the
primary pilot symbol, where the time-frequency resource locations
are in the determined time-frequency resource location range
corresponding to the primary pilot symbol;
calculating a transmit value of each auxiliary pilot symbol in the
pilot symbol group according to the obtained interference
coefficient values and the obtained transmit values of the data
symbols at the time-frequency resource locations in the
time-frequency resource location range in which each primary pilot
symbol is interfered with; and
sending the pilot symbol group, where the pilot symbol group
includes the calculated transmit values of the auxiliary pilot
symbols.
In a first possible implementation manner of the seventh aspect of
the embodiments of the present disclosure, the inserting, by the
processor, a pilot symbol group at four consecutive FBMC
time-frequency resource locations includes:
respectively inserting a first auxiliary pilot symbol, a first
primary pilot symbol, a second primary pilot symbol, and a second
auxiliary pilot symbol at a K.sup.th, a (K+1).sup.th, a
(K+2).sup.th, and a (K+3).sup.th FBMC symbol locations on a same
subcarrier at the time-frequency resource locations, where K is a
natural number; or respectively inserting a first auxiliary pilot
symbol, a first primary pilot symbol, a second primary pilot
symbol, and a second auxiliary pilot symbol on a N.sup.th, a
(N+1).sup.th, a (N+2).sup.thand a (N+3).sup.th FBMC subcarriers at
a same FBMC symbol location at the time-frequency resource
locations, where N is a natural number.
With reference to an implementation manner of the seventh aspect of
the embodiments of the present disclosure or the first possible
implementation manner of the seventh aspect of the embodiments of
the present disclosure, in a second possible implementation manner
of the seventh aspect of the embodiments of the present disclosure,
the determining, by the processor, a time-frequency resource
location range in which the primary pilot symbol is interfered with
includes:
for each primary pilot symbol in the pilot symbol group,
determining, according to the multiplex converter response data and
a time-frequency resource location of the primary pilot symbol, the
time-frequency resource location range in which the primary pilot
symbol is interfered with.
With reference to the implementation manner of the seventh aspect
of the embodiments of the present disclosure or the first possible
implementation manner of the seventh aspect of the embodiments of
the present disclosure, in a third possible implementation manner
of the seventh aspect of the embodiments of the present disclosure,
the determining, by the processor, a time-frequency resource
location range in which the primary pilot symbol is interfered with
includes:
obtaining a preset time-frequency resource location range in which
the primary pilot symbol is interfered with.
With reference to the implementation manner of the seventh aspect
of the embodiments of the present disclosure or the first possible
implementation manner of the seventh aspect of the embodiments of
the present disclosure, in a fourth possible implementation manner
of the seventh aspect of the embodiments of the present disclosure,
the determining, by the processor, a time-frequency resource
location range in which the primary pilot symbol is interfered with
includes:
determining, based on an interference estimation algorithm, the
time-frequency resource location range in which the primary pilot
symbol is interfered with.
With reference to any one of the implementation manner of the
seventh aspect of the embodiments of the present disclosure or the
first to the fourth possible implementation manners of the seventh
aspect of the embodiments of the present disclosure, in a fifth
possible implementation manner of the seventh aspect of the
embodiments of the present disclosure, the calculating, by the
processor, a transmit value of each auxiliary pilot symbol in the
pilot symbol group according to the obtained interference
coefficient values and the obtained transmit values of the data
symbols at the time-frequency resource locations in the
time-frequency resource location range in which each primary pilot
symbol is interfered with includes:
for an auxiliary pilot symbol adjacent to the primary pilot symbol
in the pilot symbol group, adding up values obtained after
separately multiplying the obtained transmit values of the data
symbols corresponding to the primary pilot symbol by the
interference coefficient values of the interference caused at the
time-frequency resource locations of the data symbols to the
primary pilot symbol, and using the calculated added result as a
first result;
dividing the first result by an interference coefficient value of
interference caused at a time-frequency resource location of the
auxiliary pilot symbol to the primary pilot symbol, and using the
calculated result as a second result; and
determining a value obtained after the second result is negated as
the transmit value of the auxiliary pilot symbol.
With reference to the fifth possible implementation manner of the
seventh aspect of the embodiments of the present disclosure, in a
sixth possible implementation manner of the seventh aspect of the
embodiments of the present disclosure, when time-frequency resource
locations at which the first auxiliary pilot symbol, the first
primary pilot symbol, the second primary pilot symbol, and the
second auxiliary pilot symbol in the pilot symbol group are located
are
(m.sub.k,n.sub.k),(m.sub.k,n.sub.k+1),(m.sub.k,n.sub.k+2),(m.sub.k,n.sub.-
k+3); a time-frequency resource location range in which the first
primary pilot symbol is interfered with is {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+1; a time-frequency resource
location range in which the second primary pilot symbol is
interfered with is {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+2; the first auxiliary pilot
symbol and the second auxiliary pilot symbol of a transmit antenna
port j are respectively a.sub.m.sub.k.sub.,n.sub.k.sup.j and
a.sub.m.sub.k.sub.,n.sub.k+3.sup.j; a transmit value of a data
symbol at a time-frequency resource location (m, n) on the transmit
antenna port j is a.sub.m,n.sup.j; an interference coefficient
value of interference caused at the time-frequency resource
location (m, n) to the first primary pilot symbol is
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+1.sub.), where the
time-frequency resource location (m, n) is in the time-frequency
resource location range corresponding to the first primary pilot
symbol; and an interference coefficient value of interference
caused at the time-frequency resource location (m, n) to the second
primary pilot symbol is
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+2.sub.), where the
time-frequency resource location (m, n) is in the time-frequency
resource location range corresponding to the second primary pilot
symbol, transmit values of the first auxiliary pilot symbol
a.sub.m.sub.k.sub.,n.sub.k.sup.j and the second auxiliary pilot
symbol a.sub.m.sub.k.sub.,n.sub.k+3.sup.j in the pilot symbol group
are specifically:
.di-elect cons..OMEGA..times..times..times..zeta..zeta.
##EQU00003## .di-elect
cons..OMEGA..times..times..times..times..zeta..zeta.
##EQU00003.2##
where
{hacek over (.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+1={(m,n),
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+1.sub.).noteq.0, and
(m,n).noteq.{(m.sub.k,n.sub.k),(m.sub.k,n.sub.k+1),(m.sub.k,n.sub.k+2)}},
{hacek over (.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+2={(m,n),
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+2.sub.).noteq.0, and
(m,n).noteq.{(m.sub.k,n.sub.k+3),(m.sub.k,n.sub.k+3),(m.sub.k,n.sub.k+2)}-
}.
With reference to any one of the seventh aspect of the embodiments
of the present disclosure or the first to the sixth possible
implementation manners of the seventh aspect of the embodiments of
the present disclosure, in a seventh possible implementation manner
of the seventh aspect of the embodiments of the present disclosure,
the processor sends primary pilot symbols on different transmit
antenna ports in a code division manner.
An eighth aspect of the embodiments of the present disclosure
discloses a receiving device, including: a processor, at least one
receive antenna port connected to the processor by using an
interface, and a memory connected to the processor by using a bus,
where the memory stores a group of program code, and the processor
is configured to invoke the program code stored in the memory to
perform the following operations:
obtaining receive values at time-frequency resource locations at
which primary pilot symbols sent from each transmit antenna port to
each receive antenna port are located, where interference caused by
other data symbols to the primary pilot symbols is cancelled for
the receive values by using auxiliary pilot symbols;
determining a receiving sequence from each transmit antenna port to
each receive antenna port; and
calculating, for each transmit antenna port to each receive antenna
port, an estimation value of a channel between the transmit antenna
port and the receive antenna port according to the receive values
of the primary pilot symbols and the receiving sequence.
In a first possible implementation manner of the eighth aspect of
the embodiments of the present disclosure, the determining, by the
processor, a receiving sequence from each transmit antenna port to
each receive antenna port includes:
obtaining an interference response matrix for the time-frequency
resource locations at which the primary pilot symbols at a transmit
end are located;
obtaining a transmit matrix that includes transmit values of
primary pilot symbols at the transmit end; and
calculating the receiving sequence from each transmit antenna port
to each receive antenna port according to the interference response
matrix and the transmit matrix.
With reference to the first possible implementation manner of the
eighth aspect of the embodiments of the present disclosure, in a
second possible implementation manner of the eighth aspect of the
embodiments of the present disclosure, when the interference
response matrix of the transmit end is .GAMMA., the transmit matrix
of the transmit end is P, and a receiving sequence of a transmit
antenna port j is [b.sup.j.sub.0, b.sup.j.sub.1, . . . ,
b.sup.j.sub.n].sup.T, the calculating, by the processor, the
receiving sequence of the transmit antenna port is
specifically:
[b.sup.j.sub.0, b.sup.j.sub.1, . . . ,
b.sup.j.sub.n].sup.T=.GAMMA..sup.-1P.sup.-1 (0, . . . , 0, w.sub.j,
0, . . . , 0).sup.T, where b.sup.j.sub.n is a receiving sequence at
a time-frequency resource location at which the n.sup.th primary
pilot symbol of the transmit antenna port j is located, w.sub.j
indicates pilot channel estimation gain power of the transmit
antenna port j, a quantity of 0s in (0, . . . , 0, w.sub.j, 0, . .
. , 0).sup.T is equal to n-1, w.sub.j in (0, . . . , 0, w.sub.j, 0,
. . . , 0).sup.T appears at the j.sup.th location, and values at
other locations are 0.
In a third possible implementation manner of the eighth aspect of
the embodiments of the present, the calculating, by the processor
for each transmit antenna port to each receive antenna port, an
estimation value of a channel between the transmit antenna port and
the receive antenna port according to the receive values of the
primary pilot symbols and the receiving sequence includes:
for each transmit antenna port to each receive antenna port,
calculating a product of row vectors that include the receive
values of the primary pilot symbols and column vectors that include
the receiving sequence of the transmit antenna port; and
calculating a ratio of the product result to pilot channel
estimation gain power of the transmit antenna port, and using the
ratio as the estimation value of the channel between the transmit
antenna port and the receive antenna port.
With reference to the third possible implementation manner of the
eighth aspect of the embodiments of the present disclosure, in a
fourth possible implementation manner of the eighth aspect of the
embodiments of the present disclosure, for each transmit antenna
port on each receive antenna port, when receive values of primary
pilot symbols of a receive antenna port i are separately
r.sup.i.sub.0, r.sup.i.sub.1, . . . , r.sup.i.sub.n, where
r.sup.i.sub.n is a receive value at a time-frequency resource
location at which the n.sup.th primary pilot symbol of the receive
antenna port i is located, and an estimation value of a channel
between the transmit antenna port j and the receive antenna port i
is H.sub.ij, the calculating, by the processor, an estimation value
of a channel between the transmit antenna port and the receive
antenna port is specifically:
H.sub.ij=[r.sup.i.sub.0,r.sup.i.sub.1, . . .
,r.sup.i.sub.n][b.sup.j.sub.0,b.sup.j.sub.1, . . .
,b.sup.j.sub.n].sup.T/w.sub.j.
With reference to the first possible implementation manner of the
eighth aspect of the embodiments of the present disclosure, in a
fifth possible implementation manner of the eighth aspect of the
embodiments of the present disclosure, the obtaining, by the
processor, an interference response matrix for the time-frequency
resource locations at which the primary pilot symbols at a transmit
end are located includes:
receiving an interference response matrix indication message sent
by the transmit end; and
determining the interference response matrix for the time-frequency
resource locations of the primary pilot symbols at the transmit end
according to the interference response matrix indication
message.
With reference to the first possible implementation manner of the
eighth aspect of the embodiments of the present disclosure, in a
sixth possible implementation manner of the eighth aspect of the
embodiments of the present disclosure, the obtaining, by the
processor, an interference response matrix for the time-frequency
resource locations at which the primary pilot symbols at a transmit
end are located includes:
determining time-frequency resource locations, in a pilot symbol
group, at which the primary pilot symbols at the transmit end are
interfered with;
obtaining interference coefficient values of interference caused at
the determined time-frequency resource locations in the pilot
symbol group to the primary pilot symbols; and
constructing the interference response matrix by using the
interference coefficient values.
With reference to the sixth possible implementation manner of the
eighth aspect of the embodiments of the present disclosure, in a
seventh possible implementation manner of the eighth aspect of the
embodiments of the present disclosure, the determining, by the
processor, time-frequency resource locations, in a pilot symbol
group, at which the primary pilot symbols at the transmit end are
interfered with includes:
for each primary pilot symbol in the pilot symbol group,
determining, according to multiplex converter response data and a
time-frequency resource location of the primary pilot symbol, the
time-frequency resource location at which the primary pilot symbol
is interfered with.
With reference to the sixth possible implementation manner of the
eighth aspect of the embodiments of the present disclosure, in an
eighth possible implementation manner of the eighth aspect of the
embodiments of the present disclosure, the determining, by the
processor, time-frequency resource locations, in a pilot symbol
group, at which the primary pilot symbols at the transmit end are
interfered with includes:
obtaining preset time-frequency resource locations, in the pilot
symbol group, at which the primary pilot symbols are interfered
with.
With reference to the sixth possible implementation manner of the
eighth aspect of the embodiments of the present disclosure, in a
ninth possible implementation manner of the eighth aspect of the
embodiments of the present disclosure, the determining, by the
processor, time-frequency resource locations, in a pilot symbol
group, at which the primary pilot symbols at the transmit end are
interfered with includes:
receiving an interference indication message sent by the transmit
end; and
determining, according to the interference indication message, the
time-frequency resource locations, in the pilot symbol group, at
which the primary pilot symbols at the transmit end are interfered
with.
With reference to the sixth possible implementation manner of the
eighth aspect of the embodiments of the present disclosure, in a
tenth possible implementation manner of the eighth aspect of the
embodiments of the present disclosure, the obtaining, by the
processor, interference coefficient values of interference caused
at the determined time-frequency resource locations in the pilot
symbol group to the primary pilot symbols includes:
obtaining, according to multiplex converter response data, the
interference coefficient values of the interference caused at the
determined time-frequency resource locations to the primary pilot
symbols.
With reference to the sixth possible implementation manner of the
eighth aspect of the embodiments of the present disclosure, in an
eleventh possible implementation manner of the eighth aspect of the
embodiments of the present disclosure, the obtaining, by the
processor, interference coefficient values of interference caused
at the determined time-frequency resource locations in the pilot
symbol group to the primary pilot symbols includes:
receiving an interference coefficient table indication message sent
by the transmit end; and
obtaining the interference coefficient values, in the interference
coefficient table indication message, of the interference caused at
the determined time-frequency resource locations to the primary
pilot symbols.
With reference to any one of the eighth aspect of the embodiments
of the present disclosure or the first to the eleventh possible
implementation manners of the eighth aspect of the embodiments of
the present disclosure, in a twelfth possible implementation manner
of the eighth aspect of the embodiments of the present disclosure,
the processor distinguishes, in a code division manner, primary
pilot symbols that are on different transmit antenna ports are sent
by the transmit end.
Compared with the prior art, the embodiments of the present
disclosure have the following beneficial effects:
In the embodiments of the present disclosure, for each transmit
antenna port, a transmit end inserts a pilot symbol group at four
FBMC consecutive time-frequency resource locations, and calculates
a transmit value of each auxiliary pilot symbol in the pilot symbol
group according to determined interference coefficient values of
interference caused to each primary pilot symbol and determined
transmit values of data symbols at time-frequency resource
locations in a time-frequency resource location range in which the
primary pilot symbol is interfered with. Then, the transmit end
sends the pilot symbol group, so as to cancel interference caused
by the data symbols to the primary pilot symbol in the pilot symbol
group. A receive end obtains receive values at time-frequency
resource locations at which primary pilot symbols sent from each
transmit antenna port to each receive antenna port are located, and
then determines a receiving sequence from each transmit antenna
port to each receive antenna port. The receive end calculates an
estimation value of a channel between the transmit antenna port and
the receive antenna port according to the receive values and the
receiving sequence of the transmit antenna port on each receive
antenna port. By implementing the embodiments of the present
disclosure, pilot overheads and a power increase caused by an
auxiliary pilot symbol can be reduced, and channel estimation
performance can be improved.
BRIEF DESCRIPTION OF DRAWINGS
To describe the technical solutions in the embodiments of the
present disclosure more clearly, the following briefly introduces
the accompanying drawings required for describing the embodiments.
Apparently, the accompanying drawings in the following description
show merely some embodiments of the present disclosure, and a
person of ordinary skill in the art may still derive other drawings
from these accompanying drawings without creative efforts.
FIG. 1 is a schematic flowchart of an FBMC-based pilot sending
method disclosed in an embodiment of the present disclosure;
FIG. 2 is a specific distribution pattern of a pilot symbol group
disclosed in an embodiment of the present disclosure;
FIG. 3 is a schematic flowchart of another FBMC-based pilot sending
method disclosed in an embodiment of the present disclosure;
FIG. 4 is a schematic flowchart of a channel estimation method
disclosed in an embodiment of the present disclosure;
FIG. 5 is a schematic flowchart of another channel estimation
method disclosed in an embodiment of the present disclosure;
FIG. 6 is another specific distribution pattern of pilot symbol
groups disclosed in an embodiment of the present disclosure;
FIG. 7 is a throughput emulation result of an FBMC system that uses
an FBMC-based pilot sending method and a channel estimation method
disclosed in embodiments of the present disclosure;
FIG. 8 is a schematic structural diagram of an FBMC-based pilot
sending apparatus disclosed in an embodiment of the present
disclosure;
FIG. 9 is a schematic structural diagram of another FBMC-based
pilot sending apparatus disclosed in an embodiment of the present
disclosure;
FIG. 10 is a schematic structural diagram of a channel estimation
apparatus disclosed in an embodiment of the present disclosure;
FIG. 11 is a schematic structural diagram of another channel
estimation apparatus disclosed in an embodiment of the present
disclosure;
FIG. 12 is a schematic structural diagram of a sending device
disclosed in an embodiment of the present disclosure; and
FIG. 13 is a schematic structural diagram of a receiving device
disclosed in an embodiment of the present disclosure.
DESCRIPTION OF EMBODIMENTS
The following clearly describes the technical solutions in the
embodiments of the present disclosure with reference to the
accompanying drawings in the embodiments of the present disclosure.
Apparently, the described embodiments are merely a part rather than
all of the embodiments of the present disclosure. All other
embodiments obtained by a person of ordinary skill in the art based
on the embodiments of the present disclosure without creative
efforts shall fall within the protection scope of the present
disclosure.
Embodiments of the present disclosure disclose an FBMC-based pilot
sending method, a channel estimation method, and a related
apparatus, which are used to reduce pilot overheads and a power
increase caused by an auxiliary pilot, and improve channel
estimation performance. Details are separately illustrated in the
following.
Referring to FIG. 1, FIG. 1 is a schematic flowchart of an
FBMC-based pilot sending method disclosed in an embodiment of the
present disclosure. The method shown in FIG. 1 may be executed by
user equipment or a mobile station that serves as a transmit end,
or may be any other device that can work in a wireless environment,
which is not limited in this embodiment of the present disclosure.
As shown in FIG. 1, the pilot sending method includes the following
steps.
S101. For each transmit antenna port, a transmit end inserts a
pilot symbol group at four consecutive time-frequency resource
locations, where the pilot symbol group includes two auxiliary
pilot symbols and two primary pilot symbols.
That for each transmit antenna port, a transmit end inserts a pilot
symbol group at four consecutive time-frequency resource locations
is specifically: the transmit end respectively inserts a first
auxiliary pilot symbol, a first primary pilot symbol, a second
primary pilot symbol, and a second auxiliary pilot symbol at the
K.sup.th, the (K+1).sup.th, the (K+2).sup.th, and the (K+3).sup.th
FBMC symbol locations on a same subcarrier at the time-frequency
resource locations, where K is a natural number; or respectively
inserts a first auxiliary pilot symbol, a first primary pilot
symbol, a second primary pilot symbol, and a second auxiliary pilot
symbol on the N.sup.th, the (N+1).sup.th, the (N+2).sup.th, and the
(N+3).sup.th FBMC subcarriers at a same FBMC symbol location at the
time-frequency resource locations, where N is a natural number. The
transmit end may insert a corresponding quantity of pilot symbol
groups on each transmit antenna port according to a coherence time
and coherence bandwidth of a system, that is, determine
distribution density of pilot symbol groups.
For example, locations of pilot symbols in pilot symbol groups
inserted on a transmit antenna port j by the transmit end are shown
in a pilot pattern in FIG. 2. The pilot pattern includes data
symbols (as shown in FIG. 2, a blank circle represents a data
symbol), the first auxiliary pilot symbol a.sup.j.sub.m0,n0, the
first primary pilot symbol p.sup.j.sub.m0,n1, the second primary
pilot symbol p.sup.j.sub.m0,n2, and the second auxiliary pilot
symbol a.sup.j.sub.m0,n3 in the pilot symbol group (as shown in
FIG. 2, a grid circle represents an auxiliary pilot symbol, and a
striped circle represents a primary pilot symbol).
S102. For each primary pilot symbol, the transmit end determines a
time-frequency resource location range in which the primary pilot
symbol is interfered with.
In an optional implementation manner, that the transmit end
determines the time-frequency resource location range of other
time-frequency resource locations at which each primary pilot
symbol is interfered with may be determining, for each primary
pilot symbol in the pilot symbol group according to multiplex
converter response data and a time-frequency resource location of
the primary pilot symbol, the time-frequency resource location
range in which the primary pilot symbol is interfered with.
In another optional implementation manner, the transmit end may
obtain a preset time-frequency resource location range in which the
primary pilot symbol is interfered with. For example, once an FBMC
or MIMO-FBMC system is determined, a filter or an overlapping
factor that is used by the system is determined, that is, the
time-frequency resource location range in which the primary pilot
symbol is interfered with is determined. To reduce operation load
of the transmit end, the time-frequency resource location range may
be built into the system. Once the system is started, the transmit
end can obtain the time-frequency resource location range for each
primary pilot symbol.
In another optional implementation manner, the transmit end may
determine, based on an interference estimation algorithm, the
time-frequency resource location range in which the primary pilot
symbol is interfered with. Specifically, the interference
estimation algorithm means that the transmit end calculates
interference coefficient power in a range according to multiplex
converter response data. If interference coefficient power in a
range is not greater than a threshold, it is considered that
interference outside this range may be ignored, and this range is
determined as the time-frequency resource location range in which
the primary pilot symbol is interfered with. For example, for an
IOTA filter, a specified threshold is that when interference
coefficient power at a time-frequency resource location is less
than 2% of total interference coefficient power, interference
caused at the time-frequency resource location to the primary pilot
symbol is ignored. Total interference coefficient power in a
3.times.3 time-frequency resource location range is 0.9877, and
interference coefficient power outside this range is only 0.0123.
That is, interference caused at another time-frequency resource
location outside the 3.times.3 time-frequency resource location
range to the primary pilot symbol is less than 2% of the total
interference coefficient power, and it is considered that the
time-frequency resource location range in which the primary pilot
symbol is interfered with is 3.times.3.
S103. For each primary pilot symbol, the transmit end obtains
transmit values of data symbols at time-frequency resource
locations in the determined time-frequency resource location range
corresponding to the primary pilot symbol.
S104. For each primary pilot symbol, the transmit end obtains,
according to multiplex converter response data, interference
coefficient values of interference caused at the time-frequency
resource locations to the primary pilot symbol, where the
time-frequency resource locations are in the determined
time-frequency resource location range corresponding to the primary
pilot symbol.
TABLE-US-00001 TABLE 1 Subcarrier Symbol number -1 0 1 -1 0.2280j
-0.4411j 0.2280j 0 -0.4411j 1 -0.4411j 1 0.2280j -0.4411j
0.2280j
In an optional implementation manner, the interference coefficient
values of the interference caused at the time-frequency resource
locations to the primary pilot symbol may be obtained according to
an FBMC multiplex converter response, where the time-frequency
resource locations are in the determined time-frequency resource
location range corresponding to the primary pilot symbol. For
example, Table 1 is a multiplex converter response (which uses an
IOTA filter) in an FBMC system, and is used to indicate receive
values, at time-frequency resource locations of a receive end, that
are obtained when a transmit value at a central time-frequency
resource location (0, 0) is 1 and transmit values at other
time-frequency resource locations are 0. Rows in Table 1 indicate
subcarrier numbers, columns indicate numbers of FBMC symbols in a
time domain, and elements in the table are multiplex converter
response data in an FBMC system. If the primary pilot symbol is
sent at the central time-frequency resource location, the
time-frequency resource location range in which the primary pilot
symbol is interfered with is 3.times.3. That is, symbols in a range
with two left symbols adjacent to the primary pilot symbol, two
right symbols adjacent to the primary pilot symbol, two adjacent
subcarriers above the primary pilot symbol, and two adjacent
subcarriers below the primary pilot symbol cause interference to
the primary pilot symbol. In this case, an interference coefficient
value of interference caused by a symbol sent at a time-frequency
resource location (m, n) to the primary pilot symbol sent at the
central time-frequency resource location is response data at a
location (-m, -n) shown in Table 1. For example, as shown in Table
1, an interference value caused at a time-frequency resource
location (-1, -1) to the central time-frequency resource location
(0, 0) is 0.2280j.
TABLE-US-00002 TABLE 2 Subcarrier Symbol Number -1 0 1 -1 0.2280j
0.4411j 0.2280j 0 -0.4411j 1 0.4411j 1 0.2280j -0.4411j 0.2280j
In another optional implementation manner, an interference
coefficient table may be determined according to multiplex
converter response data. The interference coefficient values of the
interference caused at the time-frequency resource locations to the
primary pilot symbol are obtained from the interference coefficient
table, where the time-frequency resource locations are in the
determined time-frequency resource location range corresponding to
the primary pilot symbol. For example, Table 2 is an interference
coefficient table obtained according to Table 1, and is used to
represent interference coefficient values of interference caused at
other time-frequency resource locations to the central
time-frequency resource location (0, 0). Optionally, an
interference coefficient table of the filter may be stored in the
FBMC system in advance. In this way, the interference coefficient
values of the interference caused to the primary pilot symbol may
be directly determined according to the interference coefficient
table and the determined time-frequency resource location range in
which the primary pilot symbol is interfered with.
In still another optional implementation manner, the interference
coefficient table may be preset in a system, and the transmit end
directly obtains, according to the preset interference coefficient
table, the interference coefficient values of the interference
caused at the time-frequency resource locations to the primary
pilot symbol, where the time-frequency resource locations are in
the determined time-frequency resource location range corresponding
to the primary pilot symbol.
For an FBMC system, if a primary pilot symbol, in a pilot symbol
group, that is used for channel estimation and is sent at a
time-frequency resource location (m.sub.0, n.sub.1) on a transmit
antenna port j is p.sup.j.sub.m0,n1, a receive symbol at the
time-frequency resource location on a receive antenna port i of a
receive end may be approximately indicated as formula (1):
.gamma..times..times..times..times..times..times..times..times..times..ti-
mes..times..times..times..di-elect
cons..OMEGA..times..times..times..times..times..times..xi..eta..times..di-
-elect cons..OMEGA..times..times..times..times..times..times..xi.
##EQU00004##
In the formula, i indicates the i.sup.th receive antenna;
.OMEGA..sub.m0,n1 indicates a time-frequency resource location
range in which the primary pilot symbol is interfered with;
H.sup.ij.sub.m0,n1 indicates a coefficient that is of a frequency
domain channel between the transmit antenna port j and the receive
antenna port i and is at the time-frequency resource location
(m.sub.0, n.sub.1); .xi..sub.(m-m.sub.0.sub.,n-n.sub.1.sub.)
indicates an interference coefficient value of interference caused
by a transmit signal (for example, a data symbol) at a
time-frequency resource location (m, n) to the location (m.sub.0,
n.sub.1) at which the primary pilot symbol is located, where the
time-frequency resource location (m, n) is in the time-frequency
resource location range in which the primary pilot symbol is
interfered with, and the interference coefficient value may be
obtained by using step S104; and
.eta..sub.m.sub.0.sub.,n.sub.1.sup.i indicates modulation noise of
the i.sup.th receive antenna port.
To improve channel estimation performance, as shown in the formula
(2) in the formula (1), interference caused to the primary pilot
symbol by data symbols in the time-frequency resource location
range in which the primary pilot symbol is interfered with needs to
be offset by using an auxiliary pilot symbol. Specifically, after
obtaining results of execution in S103 and S104, the transmit end
achieves this effect by using the following step S105.
Further, steps S102, S103, and S104 may be executed in sequence; or
S102 and S104 are executed first, and then S103 is executed; or
steps S102 and S104 are combined and then executed. For example, if
an interference coefficient table preset in a system or a multiplex
converter response of a filter includes an interference range and
interference coefficient information of the filter, a
time-frequency resource range in which the primary pilot symbol is
interfered with and the interference coefficient values of the
interference caused at the time-frequency resource locations in the
time-frequency resource range to the primary pilot symbol can be
determined according to only the interference coefficient table or
multiplex converter response data of the filter.
S105. The transmit end calculates a transmit value of each
auxiliary pilot symbol in the pilot symbol group according to the
obtained interference coefficient values and the obtained transmit
values of the data symbols corresponding to each primary pilot
symbol.
Specifically, for an auxiliary pilot symbol adjacent to the primary
pilot symbol in the pilot symbol group, the transmit end adds up
values obtained after separately multiplying the obtained transmit
values of the data symbols corresponding to the primary pilot
symbol by the interference coefficient values of the interference
caused at the time-frequency resource locations corresponding to
the data symbols to the primary pilot symbol, and uses the
calculated added result as a first result. Then, the transmit end
divides the first result by an interference coefficient value of
interference caused at a time-frequency resource location of the
auxiliary pilot symbol to the primary pilot symbol, and uses the
calculated result as a second result. Finally, the transmit end
determines a value obtained after the second result is negated as
the transmit value of the auxiliary pilot symbol. When the transmit
value of the auxiliary pilot symbol is being calculated, only the
interference caused by the data symbols at the time-frequency
resource locations in the time-frequency resource location range to
the primary pilot symbol is considered, and there is no need to
consider interference between the primary pilot symbols and
transmit values of primary pilot symbols.
S106. The transmit end sends the pilot symbol group, where the
pilot symbol group includes the calculated transmit values of the
auxiliary pilot symbols.
Specifically, after calculating the transmit values of all the
auxiliary pilot symbols in the pilot symbol group, the transmit end
sends the pilot symbol group inserted on the transmit antenna port,
so that after receiving a signal, a receive end performs channel
estimation according to primary pilot symbols in pilot symbol
groups, on a receive antenna port, that are sent from transmit
antenna ports.
Further, the transmit end sends primary pilot symbols on different
transmit antenna ports in a code division manner.
In this embodiment of the present disclosure, a transmit end
inserts a pilot symbol group on a transmit antenna port, and two
auxiliary pilot symbols and two primary pilot symbols in the pilot
symbol group are sequentially inserted at corresponding
time-frequency resource locations. Then, for each primary pilot
symbol, the transmit end separately obtains a time-frequency
resource location range in which the primary pilot symbol is
interfered with and transmit values of data symbols at
time-frequency resource locations in the time-frequency resource
location range; determines, according to multiplex converter
response data, interference coefficient values caused at the
time-frequency resource locations in the time-frequency resource
location range to the primary pilot symbol; and determines a
transmit value of an auxiliary pilot symbol adjacent to the primary
pilot symbol according to the transmit values of the data symbols
in the time-frequency resource location range and the corresponding
interference coefficient values. After the pilot symbol group (the
pilot symbol group includes the calculated transmit values of the
auxiliary pilot symbols) is sent, interference caused by the data
symbols at the time-frequency resource locations in the
time-frequency resource location range to the primary pilot symbol
may be effectively cancelled for a receive value that is obtained
by a receive end and is at a time-frequency resource location at
which the primary pilot symbol is located, thereby laying a
foundation for improving channel estimation performance. In
addition, a power increase can be effectively reduced by using the
auxiliary pilot symbols respectively adjacent to the two primary
pilot symbols in the pilot symbol group.
Referring to FIG. 3, FIG. 3 is a schematic flowchart of another
FBMC-based pilot sending method disclosed in an embodiment of the
present disclosure. As shown in FIG. 3, the method includes the
following steps.
S201. A transmit end respectively inserts a first auxiliary pilot
symbol, a first primary pilot symbol, a second primary pilot
symbol, and a second auxiliary pilot symbol at the K.sup.th, the
(K+1).sup.th, the (K+2).sup.th, and the (K+3).sup.th FBMC symbol
locations on a same subcarrier at time-frequency resource locations
of each transmit antenna port, where K is a natural number.
A value of K depends on density of pilot symbol groups that are
inserted on the transmit antenna port and that include the first
auxiliary pilot symbol, the first primary pilot symbol, the second
primary pilot symbol, and the second auxiliary pilot symbol.
S202. The transmit end obtains a preset time-frequency resource
location range in which the primary pilot symbol is interfered
with.
Specifically, the transmit end needs to obtain time-frequency
resource location ranges in which first primary pilot symbols and
second primary pilot symbols in pilot symbol groups inserted on
transmit antenna ports are interfered with.
S203. For each primary pilot symbol, the transmit end obtains
transmit values of data symbols at time-frequency resource
locations in the determined time-frequency resource location range
corresponding to the primary pilot symbol.
S204. For an auxiliary pilot symbol adjacent to the primary pilot
symbol in the pilot symbol group, the transmit end adds up values
obtained after separately multiplying the obtained transmit values
of the data symbols corresponding to each primary pilot symbol by
interference coefficient values of interference caused at the
time-frequency resource locations corresponding to the data symbols
to the primary pilot symbol, and uses the calculated added result
as a first result.
S205. The transmit end divides the first result by an interference
coefficient value of interference caused at a time-frequency
resource location of the auxiliary pilot symbol to the primary
pilot symbol, and uses the calculated result as a second
result.
S206. The transmit end determines a value obtained after the second
result is negated as the transmit value of the auxiliary pilot
symbol.
Transmit values that are of the first auxiliary pilot symbol and
the second auxiliary pilot symbol in the pilot symbol group and are
determined in steps S204 to S206 may be calculated by using the
following formula (3). Specifically, when time-frequency resource
locations at which the first auxiliary pilot, the first primary
pilot symbol, the second primary pilot symbol, and the second
auxiliary pilot symbol in the pilot symbol group are located are
(m.sub.k,n.sub.k),(m.sub.k,n.sub.k+1),(m.sub.k,n.sub.k+2),(m.sub.k,n.sub.-
k+3); a time-frequency resource location range in which the first
primary pilot symbol is interfered with is {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+1; a time-frequency resource
location range in which the second primary pilot symbol is
interfered with is {hacek over
(.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+2; the first auxiliary pilot
symbol and the second auxiliary pilot symbol of the transmit
antenna port j are respectively a.sub.m.sub.k.sub.,n.sub.k.sup.j
and a.sub.m.sub.k.sub.,n.sub.k+3.sup.j; a transmit value of a data
symbol at a time-frequency resource location (m, n) on the transmit
antenna port j is a.sub.m,n.sup.j; an interference coefficient
value of interference caused at the time-frequency resource
location (m, n) to the first primary pilot symbol is
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+1.sub.), where the
time-frequency resource location (m, n) is in the time-frequency
resource location range corresponding to the first primary pilot
symbol; and an interference coefficient value of interference
caused at the time-frequency resource location (m, n) to the second
primary pilot symbol is
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+2.sub.), where the
time-frequency resource location (m, n) is in the time-frequency
resource location range corresponding to the second primary pilot
symbol, transmit values, calculated by the transmit end, of the
first auxiliary pilot symbol a.sub.m.sub.k.sub.,n.sub.k.sup.j and
the second auxiliary pilot symbol
a.sub.m.sub.k.sub.,n.sub.k+k.sup.j in the pilot symbol group
are:
.di-elect
cons..OMEGA..times..times..times..zeta..zeta..times..times..di--
elect cons..OMEGA..times..times..times..times..times..zeta..zeta.
##EQU00005##
where
{hacek over (.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+1={(m,n),
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+1.sub.).noteq.0, and
(m,n).noteq.{(m.sub.k,n.sub.k),(m.sub.k,n.sub.k+1),(m.sub.k,n.sub.k+2)}},
{hacek over (.OMEGA.)}.sub.m.sub.k.sub.n.sub.k+2={(m,n),
.zeta..sub.(m-m.sub.k.sub.,n-n.sub.k+2.sub.).noteq.0, and
(m,n).noteq.{(m.sub.k,n.sub.k+3),(m.sub.k,n.sub.k+1),(m.sub.k,
n.sub.k+2)}}.
S207. The transmit end sends the pilot symbol group, where the
pilot symbol group includes the calculated transmit values of the
auxiliary pilot symbols.
For an MIMO-FBMC system, the transmit end may have multiple
transmit antenna ports, and may insert pilot symbol groups of
specific density on all the transmit antenna ports according to a
requirement for channel estimation performance. Each pilot symbol
group includes a first auxiliary pilot symbol, a first primary
pilot symbol, a second primary pilot symbol, and a second auxiliary
pilot symbol at consecutive time-frequency resource locations.
Further, the transmit end sends primary pilot symbols on the
different transmit antenna ports in a code division manner.
In this embodiment of the present disclosure, a transmit end
inserts, on a transmit antenna port, a pilot symbol group that
includes a first auxiliary pilot symbol, a first primary pilot
symbol, a second primary pilot symbol, and a second auxiliary pilot
symbol at consecutive locations, so as to reduce a power increase
caused by an auxiliary pilot. The transmit end obtains a
time-frequency resource location range that is preset in an FBMC
system and in which the primary pilot symbol in the pilot symbol
group is interfered with, and determines transmit values of data
symbols in the time-frequency resource location range and
interference coefficient values, so as to calculate a transmit
value of the auxiliary pilot symbol in the pilot symbol group,
thereby cancelling interference caused by the data symbols in the
time-frequency resource location range to the primary pilot symbol,
and further improving channel estimation performance.
Referring to FIG. 4, FIG. 4 is a schematic flowchart of a channel
estimation method disclosed in an embodiment of the present
disclosure. As shown in FIG. 4, the method includes the following
steps.
S301. A receive end obtains receive values at time-frequency
resource locations at which primary pilot symbols sent from each
transmit antenna port to each receive antenna port are located,
where interference caused by other data symbols to the primary
pilot symbols is cancelled for the receive values by using
corresponding auxiliary pilot symbols.
S302. The receive end determines a receiving sequence from each
transmit antenna port to each receive antenna port.
In an optional implementation manner, the receive end may determine
the receiving sequence by using the following steps: obtaining an
interference response matrix for the time-frequency resource
locations at which the primary pilot symbols at a transmit end are
located, obtaining a transmit matrix that includes transmit values
of primary pilot symbols at the transmit end; and calculating the
receiving sequence from each transmit antenna port to each receive
antenna port according to the interference response matrix and the
transmit matrix.
The receive end may obtain, by using the following steps, the
interference response matrix required in a process of determining
the receiving sequence: receiving an interference response matrix
indication message, sent by the transmit end, for the
time-frequency resource locations at which the primary pilot
symbols are located; and determining, from the interference
response matrix indication message, the interference response
matrix for the time-frequency resource locations at which the
primary pilot symbols at the transmit end are located.
In another optional implementation manner, the receive end may
obtain, by using the following steps, the interference response
matrix required in a process of determining the receiving sequence:
determining time-frequency resource locations, in a pilot symbol
group, at which the primary pilot symbols at the transmit end are
interfered with (only interference between adjacent primary pilot
symbols is considered for the time-frequency resource locations
determined by the receive end); obtaining interference coefficient
values of interference caused at the time-frequency resource
locations to the primary pilot symbols, where the time-frequency
resource locations are in the time-frequency resource locations
corresponding to the primary pilot symbols; and constructing the
interference response matrix by using the interference coefficient
values. The interference response matrix indicates a response
matrix formed due to mutual interference between two adjacent
primary pilot symbols in a pilot symbol group. For example, in a
pilot symbol group shown in FIG. 2, it is assumed that a transmit
value of a first primary pilot symbol at a time-frequency resource
location (m.sub.0, n.sub.1) is p.sub.m0,n1, a transmit value of a
second primary pilot symbol at a time-frequency resource location
(m.sub.0, n.sub.2) is p.sub.m0,n2, an interference coefficient
value of interference caused by the second primary pilot symbol to
the first primary pilot symbol is b, and an interference
coefficient value of interference caused by the first primary pilot
symbol to the second primary pilot symbol is .gamma.. Generally,
according to the pilot symbol group sending manner shown in S101 in
the first embodiment, b=-.gamma.. Therefore, a receive signal
r.sub.m0,n1 at the time-frequency resource location (m.sub.0,
n.sub.1) at the receive end may be indicated as
r.sub.m0,n1=p.sub.m0,n1-.gamma.p.sub.m0,n2 (impact of a channel and
noise is not considered). Likewise, a receive signal r.sub.m0,n2 at
the time-frequency resource location (m.sub.0, n.sub.2) at the
receive end may be indicated as
r.sub.m0,n2=p.sub.m0,n2+.gamma.p.sub.m0,n1. In this case, the
receive signal may be:
.times..times..times..times..times..times..times..times..times..times..ga-
mma..gamma..times..times..times..times..times..times..times..times..times.
##EQU00006##
Therefore, the interference response matrix .GAMMA. constructed by
the receive end by using the interference coefficient values at the
time-frequency resource locations that are at the transmit end and
are corresponding to the primary pilot symbols is:
.GAMMA..gamma..gamma. ##EQU00007##
The receive end may directly obtain, from an interference range
indication message sent by the transmit end, the time-frequency
resource locations that are in the pilot symbol group and at which
the primary pilot symbols at the transmit end are interfered with;
or the receive end determines, according to multiplex converter
response data and time-frequency resource locations of the primary
pilot symbols, the time-frequency resource locations at which the
primary pilot symbols are interfered with; or the receive end
directly determines the interference response matrix by using
time-frequency resource locations that are preset in an FBMC system
and at which the primary pilot symbols are interfered with.
In addition, that the receive end obtains, in a process of
obtaining the interference response matrix, the interference
coefficient values that are of interference caused to the primary
pilot symbols and are corresponding to the primary pilot symbols
may be specifically obtaining, according to the multiplex converter
response data, the interference coefficient values of the
interference caused at the time-frequency resource locations
corresponding to the primary pilot symbols to the primary pilot
symbols. Optionally, the receive end may receive an interference
coefficient table indication message or a multiplex converter
response indication message sent by the transmit end, and obtain,
from the interference coefficient table indication message or the
multiplex converter response indication message, the interference
coefficient values of the interference caused at the determined
time-frequency resource locations to the primary pilot symbols.
In another optional implementation manner, the receive end may use
the following manner to determine the receiving sequence from each
transmit antenna port to each receive antenna port: The receive end
receives a receiving sequence indication message sent by the
transmit end, and the receive end determines the receiving sequence
from each transmit antenna port to each receive antenna port
according to the receiving sequence indication message.
S303. For each transmit antenna port to each receive antenna port,
the receive end calculates an estimation value of a channel between
the transmit antenna port and the receive antenna port according to
the receive values of the primary pilot symbols and the receiving
sequence.
Specifically, that the receive end calculates the estimation value
of the channel between the transmit antenna port and the receive
antenna port may include the following step: for each transmit
antenna port to each receive antenna port, calculating a product of
row vectors that include the receive values of the primary pilot
symbols and column vectors that include the receiving sequence of
the transmit antenna port; and
calculating a ratio of the product result to pilot channel
estimation gain power of the transmit antenna port, and using the
ratio as the estimation value of the channel between the transmit
antenna port and the receive antenna port.
Further, the receive end distinguishes, in a code division manner,
primary pilot symbols that are on different transmit antenna ports
and are sent by the transmit end.
In this embodiment of the present disclosure, a receive end first
obtains receive values at time-frequency resource locations at
which primary pilot symbols sent from each transmit antenna port to
each receive antenna port are located, where interference caused by
other data symbols to the primary pilot symbols is cancelled for
the receive values by using the pilot sending method, designed at a
transmit end, in the foregoing embodiment. Then, because an FBMC
system is a non-orthogonal system, the receive end needs to
determine a receiving sequence from each transmit antenna port to
each receive antenna port. Finally, the receive end calculates an
estimation value of a channel between the transmit antenna port and
the receive antenna port according to the received receive values
and the receiving sequence. With reference to the pilot sending
method in the foregoing embodiment of the present disclosure, by
using the channel estimation method in this embodiment of the
present disclosure, transmit power of an auxiliary pilot symbol can
be effectively decreased, thereby reducing a power increase caused
by an auxiliary pilot symbol, and optimizing channel estimation
performance.
Referring to FIG. 5, FIG. 5 is a schematic flowchart of another
channel estimation method disclosed in an embodiment of the present
disclosure. The channel estimation method shown in FIG. 5 is
obtained by further optimizing the channel estimation method shown
in FIG. 4. As shown in FIG. 5, the method includes the following
steps.
S401. A receive end obtains receive values at time-frequency
resource locations at which primary pilot symbols sent from each
transmit antenna port to each receive antenna port are located,
where interference caused by other data symbols to the primary
pilot symbols is cancelled for the receive values by using
corresponding auxiliary pilot symbols.
S402. The receive end obtains an interference response matrix for
the time-frequency resource locations at which the primary pilot
symbols at a transmit end are located.
S403. The receive end obtains a transmit matrix that includes
transmit values of primary pilot symbols at the transmit end.
S404. The receive end calculates a receiving sequence from each
transmit antenna port to each receive antenna port according to the
interference response matrix and the transmit matrix of the
transmit end.
A 1.times.2 MIMO-FBMC system is used as an example. An estimation
value of a channel between a transmit antenna port 0 and a receive
antenna port is represented as H.sub.0, an estimation value of a
channel between a transmit antenna port 1 and the receive antenna
port is represented as H.sub.1, pilot channel estimation gain power
that is of the transmit antenna port 0 and is obtained by the
receive end by using step S401 is w.sub.0, pilot channel estimation
gain power of the transmit antenna port 1 is w.sub.1, the
interference response matrix that is for the time-frequency
resource locations at which the primary pilot symbols at the
transmit end are located and that is obtained by the receive end by
using step S402 is
.GAMMA..gamma..gamma. ##EQU00008## and a transmit matrix that
includes transmit values of pilot symbols that are sent from the
transmit antenna port 0 and the transmit antenna port 1 at the
transmit end and are determined by the receive end by using step
S403 is
##EQU00009##
A receiving sequence (b.sub.0.sup.0 b.sub.1.sup.0) that is of the
transmit antenna port 0 and is obtained by the receive end by means
of calculation by using step S405 is specifically:
(b.sub.0.sup.0b.sub.1.sup.0).sup.T=.GAMMA..sup.-1P.sup.-1(w.sub.00).sup.T
(6)
A receiving sequence (b.sub.0.sup.1 b.sub.1.sup.1 ) that is of the
transmit antenna port 1 and is obtained by the receive end by means
of calculation by using step S405 is specifically:
(b.sub.0.sup.1b.sub.0.sup.1).sup.T=.GAMMA..sup.-1P.sup.-1(0
w.sub.1).sup.T (7)
The pilot channel estimation gain power indicates a ratio of joint
pilot power for performing channel estimation by the receive end to
power of a pilot symbol sent by the transmit end. For example, a
CRS pilot in an MIMO-OFDM system is used as an example. A CRS pilot
is sent in a time division or frequency division manner. The
transmit end sends, at a time-frequency resource location (m, n), a
pilot symbol P.sub.m,n whose transmit power is P. A value received
by the receive end at the time-frequency resource location (m, n)
is r.sub.m,n=H.sub.m,np.sub.m,n+n.sub.m,n. H.sub.m,n indicates a
frequency domain channel coefficient at the time-frequency resource
location (m, n), and n.sub.m,n indicates noise at the
time-frequency resource location (m, n). Channel estimation is
performed by using a formula
r.sub.m,np*.sub.m,n=H.sub.m,np.sub.m,np*.sub.m,n+n.sub.m,np*.sub.m,n=H.su-
b.m,n.parallel.p.sub.m,n.parallel..sup.2+n.sub.m,np*.sub.m,n, where
* indicates performing conjugating on a variable, and .parallel.
.parallel. indicates taking an absolute value of a variable.
Because channel estimation is independently performed at the
time-frequency resource location by using the CRS pilot, joint
pilot power for performing channel estimation by the receive end is
still P, and pilot channel estimation gain power of the transmit
end is 1. A DRS pilot in the MIMO-OFDM system is used as an
example. A DRS is sent in a code division manner, and channel
estimation is performed jointly by using DRSs on two adjacent pilot
symbols. Therefore, joint pilot power for channel estimation is 2P,
and pilot channel estimation gain power is 2. For the MIMO-FBMC
system, because the MIMO-FBMC system has inherent interference,
pilot channel estimation gain power in the MIMO-FBMC system is
related to an interference coefficient in the MIMO-FBMC system. The
1.times.2 MIMO-FBMC system is used as an example. It is assumed
that a transmit matrix that includes transmit values of the
transmit antenna port 0 and the transmit antenna port 1 is
##EQU00010## According to the foregoing determined interference
response matrix
.GAMMA..gamma..gamma. ##EQU00011## pilot channel estimation gain
power w.sub.0 of the transmit antenna port 0 and pilot channel
estimation gain power w.sub.1 of the transmit antenna port 1 are
w.sub.0=w.sub.1=2(1+.gamma..sup.2). The receiving sequences of the
transmit antenna port 0 and the transmit antenna port 1 may be
respectively obtained by substituting w.sub.0 and w.sub.1 into the
formula (6) and the formula (7).
.gamma..gamma..gamma..gamma. ##EQU00012##
S405. For each transmit antenna port to each receive antenna port,
the receive end calculates a product of row vectors that include
the receive values of the primary pilot symbols and column vectors
that include the receiving sequence of the transmit antenna
port.
S406. The receive end calculates a ratio of the product result to
pilot channel estimation gain power of the transmit antenna port,
and uses the ratio as an estimation value of a channel between the
transmit antenna port and the receive antenna port.
The foregoing 1.times.2 MIMO-FBMC system is still used as an
example. Receive values that are at time-frequency resource
locations at which the primary pilot symbols are located and that
are obtained by the receive end according to step S401 are
respectively r.sub.m0,n1 and r.sub.m0,n2, and the estimation value
H.sub.0 of the channel between the transmit antenna port 0 and the
receive end is specifically:
.times..times..times..times..times..times..times..times..times..times..ti-
mes. ##EQU00013##
The estimation value H.sub.1 of the channel between the transmit
antenna port 1 and the receive end is specifically:
.times..times..times..times..times..times..times..times..times..times.
##EQU00014##
Four transmit antenna ports are used as examples. Pilot symbol
groups on different antenna ports at the transmit end have same
distribution. FIG. 6 shows a distribution pattern of pilot symbol
groups on an antenna port j. A transmit value of an auxiliary pilot
symbol in the pilot symbol group is calculated by using the pilot
sending method described in the foregoing embodiment of the present
disclosure, so as to cancel interference caused by data symbols
surrounding a primary pilot symbol to the primary pilot symbol. As
shown in FIG. 6, primary pilot symbols in two pilot symbol groups
on a same subcarrier on the transmit antenna port j are
respectively represented as p.sup.j.sub.0, p.sup.j.sub.1,
p.sup.j.sub.2, and p.sup.j.sub.3, and a transmit matrix P that
includes primary pilot symbols on the four transmit antenna ports
is indicated in the following:
##EQU00015##
The interference response matrix .GAMMA. for the time-frequency
resource locations at which the primary pilot symbols are located
is indicated in the following:
.GAMMA..gamma..gamma..gamma..gamma. ##EQU00016##
A receiving sequence (b.sup.j.sub.0, b.sup.j.sub.1, b.sup.j.sub.2,
b.sup.j.sub.3).sup.T of the transmit antenna port j is indicated in
the following:
(b.sub.0.sup.jb.sub.1.sup.jb.sub.2.sup.jb.sub.3.sup.j).sup.T=.GAMMA..sup.-
-1P.sup.-1.alpha..sub.j (12)
In the formula, .alpha..sub.j indicates a column vector in which
the j.sup.th element is a non-zero element, and the non-zero
element of the column vector is pilot channel estimation gain power
W.sub.j of the j.sup.th antenna port. In this case, an estimation
value of a channel between the transmit antenna port j and a
receive antenna port i is:
.times..times. ##EQU00017##
With reference to the pilot sending method in the foregoing
embodiment, this embodiment of the present disclosure brings
beneficial effects from three aspects by implementing the channel
estimation method: First, pilot overheads are reduced. Compared
with an IAM solution, the pilot overheads are reduced by 60%.
Second, a power increase of an auxiliary pilot symbol is reduced.
Statistically, a power increase of an auxiliary pilot is reduced
by
.gamma..gamma. ##EQU00018## For example, a power increase of an
auxiliary pilot is reduced by 24% for an IOTA filter. Third,
channel estimation performance is improved. As shown in FIG. 7, an
FBMC system can obtain accurate channel estimation by using the
pilot solution described in the present disclosure. In addition,
compared with an OFDM system, the FBMC system can ensure that about
15% gains are brought to an FBMC link because a power increase of
an auxiliary pilot symbol and pilot overheads are reduced.
Referring to FIG. 8, FIG. 8 is a schematic structural diagram of an
FBMC-based pilot sending apparatus disclosed in an embodiment of
the present disclosure. As shown in FIG. 8, the apparatus includes
the following units: a pilot inserting unit 1, a first determining
unit 2, a first obtaining unit 3, a second obtaining unit 4, a
calculation unit 5, and a sending unit 6.
The pilot inserting unit 1 is configured to: for each transmit
antenna port, insert a pilot symbol group at four consecutive FBMC
time-frequency resource locations. The pilot symbol group includes
two auxiliary pilot symbols and two primary pilot symbols.
The pilot inserting unit 1 may be configured to perform the method
in step S201. The pilot inserting unit 1 may insert a corresponding
quantity of pilot symbol groups on each transmit antenna port
according to a coherence time and coherence bandwidth of a system,
to determine distribution density of pilot symbol groups.
For example, locations of pilot symbols in pilot symbol groups
inserted on a transmit antenna port j by the pilot inserting unit 1
are shown in a pilot pattern in FIG. 2. The pilot pattern includes
a first auxiliary pilot symbol a.sup.j.sub.m0,n0, a first primary
pilot symbol p.sup.j.sub.m0,n1, a second primary pilot symbol
p.sup.j.sub.m0,n2, and a second auxiliary pilot symbol
a.sup.j.sub.m0,n3.
The first determining unit 2 is configured to: for each primary
pilot symbol inserted by the pilot inserting unit 1, determine a
time-frequency resource location range in which the primary pilot
symbol is interfered with.
In an optional implementation manner, that the first determining
unit 2 determines the time-frequency resource location range in
which each primary pilot symbol is interfered with at another
time-frequency resource location may be determining, for each
primary pilot symbol in the pilot symbol group according to
multiplex converter response data and a time-frequency resource
location of the primary pilot symbol, the time-frequency resource
location range in which the primary pilot symbol is interfered
with.
In another optional implementation manner, the first determining
unit 2 may obtain a preset time-frequency resource location range
in which the primary pilot symbol is interfered with. For example,
once an FBMC or MIMO-FBMC system is determined, a filter or an
overlapping factor that is used by the system is determined, that
is, the time-frequency resource location range in which the primary
pilot symbol is interfered with is determined. To reduce operation
load of a transmit end, the time-frequency resource location range
may be built into the system. Once the system is started, the first
determining unit 2 can obtain the time-frequency resource location
range for each primary pilot symbol.
In another optional implementation manner, the first determining
unit 2 may determine, based on an interference estimation
algorithm, the time-frequency resource location range in which the
primary pilot symbol is interfered with.
The first obtaining unit 3 is configured to: for each primary pilot
symbol, obtain transmit values of data symbols at time-frequency
resource locations in the time-frequency resource location range
that is determined by the first determining unit 2 and is
corresponding to the primary pilot symbol.
The second obtaining unit 4 is configured to: for each primary
pilot symbol, obtain, according to multiplex converter response
data, interference coefficient values of interference caused at the
time-frequency resource locations to the primary pilot symbol,
where the time-frequency resource locations are in the
time-frequency resource location range that is determined by the
first determining unit 2 and that is corresponding to the primary
pilot symbol.
In an optional implementation manner, the second obtaining unit 4
may obtain, according to an FBMC multiplex converter response, the
interference coefficient values of the interference caused at the
time-frequency resource locations to the primary pilot symbol,
where the time-frequency resource locations are in the determined
time-frequency resource location range corresponding to the primary
pilot symbol. For example, Table 1 is a multiplex converter
response (which uses an IOTA filter) in an FBMC system, and is used
to indicate receive values, at time-frequency resource locations of
a receive end, that are obtained when a transmit value at a central
time-frequency resource location (0, 0) is 1 and transmit values at
other time-frequency resource locations are 0. Rows in Table 1
indicate subcarrier numbers, columns indicate numbers of FBMC
symbols in a time domain, and elements in the table are multiplex
converter response data in an FBMC system. If the primary pilot
symbol is sent at the central time-frequency resource location (0,
0), the time-frequency resource location range that is determined
by the first determining unit 2 and in which the primary pilot
symbol is interfered with is 3.times.3. That is, symbols in a range
with two left symbols adjacent to the primary pilot symbol, two
right symbols adjacent to the primary pilot symbol, two adjacent
subcarriers above the primary pilot symbol, and two adjacent
subcarriers below the primary pilot symbol cause interference to
the primary pilot symbol. In this case, an interference coefficient
value that is obtained by the second obtaining unit 4 and is of
interference caused by a symbol sent at a time-frequency resource
location (m, n) to the primary pilot symbol sent at the central
time-frequency resource location is response data at a location
(-m, -n) in Table 1. For example, as shown in Table 1, an
interference value caused at a time-frequency resource location
(-1, -1) to the central time-frequency resource location (0, 0) is
0.2280j.
In another optional implementation manner, the second obtaining
unit 4 may determine an interference coefficient table according to
multiplex converter response data, and obtain, from the
interference coefficient table, the interference coefficient values
of the interference caused at the time-frequency resource locations
to the primary pilot symbol, where the time-frequency resource
locations are in the determined time-frequency resource location
range corresponding to the primary pilot symbol. For example, Table
2 is an interference coefficient table obtained by the second
obtaining unit 4 according to Table 1, and is used to represent
interference coefficient values of interference caused at other
time-frequency resource locations to the central time-frequency
resource location (0, 0). Optionally, an interference coefficient
table of the filter may be stored in the FBMC system in advance. In
this way, the interference coefficient values of the interference
caused to the primary pilot symbol may be directly determined
according to the interference coefficient table and the determined
time-frequency resource location range in which the primary pilot
symbol is interfered with.
In still another optional implementation manner, the interference
coefficient table may be preset in a system. The second obtaining
unit 4 directly obtains, according to the preset interference
coefficient table, the interference coefficient values of the
interference caused at the time-frequency resource locations to the
primary pilot symbol, where the time-frequency resource locations
are in the determined time-frequency resource location range
corresponding to the primary pilot symbol.
For an FBMC system, if a primary pilot symbol, in a pilot symbol
group, that is used for channel estimation and is sent at a
time-frequency resource location (mo, n.sub.1) on a transmit
antenna port j is p.sup.j.sub.m0,n1, a receive symbol at the
time-frequency resource location on a receive antenna port i of a
receive end is .gamma..sub.m.sub.0.sub.,n.sub.1.sup.i in the
formula (1).
To improve channel estimation performance, as shown in a part of
the formula (2), interference caused to the primary pilot symbol by
data symbols in the time-frequency resource location range in which
the primary pilot symbol is interfered with needs to be offset by
using an auxiliary pilot symbol. Specifically, after execution
performed by the first obtaining unit 3 and the second obtaining
unit 4 is completed, the following calculation unit 5 achieves this
effect.
The calculation unit 5 is configured to calculate a transmit value
of each auxiliary pilot symbol in the pilot symbol group according
to the interference coefficient values obtained by the second
obtaining unit 4 and the transmit values that are obtained by the
first obtaining unit 3 and are of the data symbols corresponding to
each primary pilot symbol.
Specifically, the calculation unit 5 may be configured to calculate
the transmit value of each auxiliary pilot symbol in the pilot
symbol group by performing methods in steps S204 to S206.
The sending unit 6 is configured to send the pilot symbol group.
The pilot symbol group includes the transmit values that are of the
auxiliary pilot symbols and are calculated by the calculation unit
5.
Specifically, after calculating the transmit values of all the
auxiliary pilot symbols in the pilot symbol group, the sending unit
6 sends the pilot symbol group inserted on the transmit antenna
port, so that after receiving a signal, a receive end performs
channel estimation according to primary pilot symbols in pilot
symbol groups, on a receive antenna port, that are sent by the
sending unit 6 from each transmit antenna port. Further, the
sending unit 6 sends primary pilot symbols on different transmit
antenna ports in a code division manner.
In this embodiment of the present disclosure, a pilot inserting
unit 1 inserts a pilot symbol group on a transmit antenna port,
where two auxiliary pilot symbols and two primary pilot symbols in
the pilot symbol group are sequentially inserted at corresponding
time-frequency resource locations. Then, for each primary pilot
symbol, a first determining unit 2 determines a time-frequency
resource location range in which the primary pilot symbol is
interfered with, and a first obtaining unit 3 obtains transmit
values of data symbols at time-frequency resource locations in the
time-frequency resource location range. A second obtaining unit
determines, according to multiplex converter response data,
interference coefficient values caused at the time-frequency
resource locations in the time-frequency resource location range to
the primary pilot symbol. A calculation unit 5 determines a
transmit value of an auxiliary pilot symbol adjacent to the primary
pilot symbol according to the transmit values that are obtained by
the first obtaining unit 3 and are of the data symbols in the
time-frequency resource location range and the corresponding
interference coefficient values obtained by the second obtaining
unit 4. Therefore, after a sending unit 6 sends the pilot symbol
group (the pilot symbol group includes the calculated transmit
values of the auxiliary pilot symbols), interference caused by the
data symbols at the time-frequency resource locations in the
time-frequency resource location range to the primary pilot symbol
may be effectively cancelled for a receive value that is obtained
by a receive end and is at a time-frequency resource location at
which the primary pilot symbol is located, thereby laying a
foundation for improving channel estimation performance. In
addition, a power increase can be effectively reduced by using the
auxiliary pilot symbols respectively adjacent to the two primary
pilot symbols in the pilot symbol group.
Referring to FIG. 9, FIG. 9 is a schematic structural diagram of
another FBMC-based pilot sending apparatus. The FBMC-based pilot
sending apparatus shown in FIG. 9 is obtained by optimizing the
FBMC-based pilot sending apparatus shown in FIG. 8. As shown in
FIG. 9, the apparatus includes the following units: a pilot
inserting unit 1, a first determining unit 2, a first obtaining
unit 3, a second obtaining unit 4, a calculation unit 5, and a
sending unit 6.
The pilot inserting unit 1 is configured to: for each transmit
antenna port, insert a pilot symbol group at four consecutive FBMC
time-frequency resource locations. The pilot symbol group includes
two auxiliary pilot symbols and two primary pilot symbols.
The first determining unit 2 is configured to: for each primary
pilot symbol inserted by the pilot inserting unit 1, determine a
time-frequency resource location range in which the primary pilot
symbol is interfered with.
The first obtaining unit 3 is configured to: for each primary pilot
symbol, obtain transmit values of data symbols at time-frequency
resource locations, where the time-frequency resource locations are
in the time-frequency resource location range that is determined by
the first determining unit and that is corresponding to the primary
pilot symbol.
The second obtaining unit 4 is configured to: for each primary
pilot symbol, obtain, according to multiplex converter response
data, interference coefficient values of interference caused at the
time-frequency resource locations to the primary pilot symbol,
where the time-frequency resource locations are in the
time-frequency resource location range that is determined by the
first determining unit 2 and that is corresponding to the primary
pilot symbol.
The calculation unit 5 includes:
a first calculation unit 51, configured to: for an auxiliary pilot
symbol adjacent to the primary pilot symbol in the pilot symbol
group, add up values obtained after separately multiplying the
transmit values that are obtained by the first obtaining unit 3 and
are of the data symbols corresponding to each primary pilot symbol
by the interference coefficient values that are obtained by the
second obtaining unit 4 and are of the interference caused at the
time-frequency resource locations corresponding to the data symbols
to the primary pilot symbol, and use the calculated added result as
a first result;
a second calculation unit 52, configured to: divide the first
result calculated by the first calculation unit 51 by an
interference coefficient value of interference caused at a
time-frequency resource location of the auxiliary pilot symbol to
the primary pilot symbol, and use the calculated result as a second
result; and
a second determining unit 53, configured to determine a value
obtained after the second result calculated by the second
calculation unit is negated as the transmit value of the auxiliary
pilot symbol.
Specifically, the calculation unit 5 may use the formula (3) to
calculate transmit values of a first auxiliary pilot symbol and a
second auxiliary pilot symbol in the pilot symbol group inserted by
the pilot inserting unit 1.
The sending unit 6 is configured to send the pilot symbol group.
The pilot symbol group includes the transmit values that are of the
auxiliary pilot symbols and are calculated by the calculation unit
5. The sending unit 6 sends primary pilot symbols on different
transmit antenna ports in a code division manner.
In this embodiment of the present disclosure, a pilot inserting
unit inserts, on a transmit antenna port, a pilot symbol group that
includes a first auxiliary pilot symbol, a first primary pilot
symbol, a second primary pilot symbol, and a second auxiliary pilot
symbol at consecutive locations, so as to reduce a power increase
caused by an auxiliary pilot symbol. A first determining unit
determines a time-frequency resource location range that is preset
in an FBMC system and in which the primary pilot symbol in the
pilot symbol group is interfered with, a first obtaining unit
obtains transmit values of data symbols in the time-frequency
resource location range, and a second obtaining unit obtains
interference coefficient values, so that a calculation unit
calculates a transmit value of the auxiliary pilot symbol in the
pilot symbol group, thereby cancelling interference caused by the
data symbols in the time-frequency resource location range to the
primary pilot symbol, and further improving channel estimation
performance.
Referring to FIG. 10, FIG. 10 is a schematic structural diagram of
a channel estimation apparatus disclosed in an embodiment of the
present disclosure. As shown in FIG. 10, the apparatus includes the
following units: an obtaining unit 01, a determining unit 02, and a
calculation unit 03.
The obtaining unit 01 is configured to obtain receive values at
time-frequency resource locations at which primary pilot symbols
sent from each transmit antenna port to each receive antenna port
are located, where interference caused by other data symbols to the
primary pilot symbols is cancelled for the receive values by using
corresponding auxiliary pilot symbols.
The determining unit 02 is configured to determine a receiving
sequence from each transmit antenna port to each receive antenna
port.
In an optional implementation manner, the determining unit 02 may
be configured to determine the receiving sequence from each
transmit antenna port to each receive antenna port by performing
the method in steps S402 to S404.
Further, when determining the receiving sequence from each transmit
antenna port to each receive antenna port by performing the method
in steps S402 to S404, the determining unit 02 further needs to
obtain pilot channel estimation gain power of the transmit antenna
port on each receive antenna port, to calculate the receiving
sequence of the transmit antenna port.
In an optional implementation manner, the determining unit 02 may
obtain, by using the following steps, an interference response
matrix required in a process of determining the receiving sequence:
The determining unit 02 receives an interference response matrix
indication message, sent by the transmit end, for the
time-frequency resource locations at which the primary pilot
symbols are located; and determines, from the interference response
matrix indication message, the interference response matrix for the
time-frequency resource locations at which the primary pilot
symbols sent by the transmit end are located.
In another optional implementation manner, the determining unit 02
may obtain, by using the following steps, an interference response
matrix required in a process of determining the receiving sequence:
The determining unit 02 determines time-frequency resource
locations, in a pilot symbol group, at which the primary pilot
symbols at the transmit end are interfered with (only interference
between adjacent primary pilot symbols is considered for the
time-frequency resource locations determined by the determining
unit 02); obtains interference coefficient values of interference
caused at the time-frequency resource locations corresponding to
the primary pilot symbols to the primary pilot symbols; and
constructs the interference response matrix by using the
interference coefficient values. The determining unit 02 may
directly obtain, from an interference range indication message sent
by the transmit end, the time-frequency resource locations that are
in the pilot symbol group and at which the primary pilot symbols at
the transmit end are interfered with; or the determining unit 02
determines, according to multiplex converter response data and
time-frequency resource locations of the primary pilot symbols, the
time-frequency resource locations at which the primary pilot
symbols are interfered with; or the determining unit 02 determines
the interference response matrix by using time-frequency resource
locations that are preset in an FBMC system and at which the
primary pilot symbols are interfered with.
In addition, that the determining unit 02 obtains, in a process of
obtaining the interference response matrix, the interference
coefficient values of the interference caused at the time-frequency
resource locations corresponding to the primary pilot symbols to
the primary pilot symbols may be specifically obtaining, according
to the multiplex converter response data, the interference
coefficient values of the interference caused at the time-frequency
resource locations corresponding to the primary pilot symbols to
the primary pilot symbols. Optionally, the determining unit 02 may
receive an interference coefficient table indication message sent
by the transmit end, and then obtain, from the interference
coefficient table indication message, the interference coefficient
values of the interference caused at the determined time-frequency
resource locations to the primary pilot symbols.
The calculation unit 03 is configured to: for each transmit antenna
port to each receive antenna port, calculate an estimation value of
a channel between the transmit antenna port and the receive antenna
port according to the receive values obtained by the obtaining unit
01 that are of the primary pilot symbols and the receiving sequence
determined by the determining unit 02.
Specifically, the calculation unit 03 may be configured to perform
the method in steps S405 to S406 to calculate the estimation value
of the channel between the transmit antenna port and the receive
antenna port.
For each transmit antenna port on each receive antenna port, it is
assumed that receive values of primary pilot symbols of the receive
antenna port i are respectively r.sup.i.sub.0, r.sup.i.sub.1, . . .
, r.sup.i.sub.n, where r.sup.i.sub.n is a receive value at a
time-frequency resource location at which the n.sup.th primary
pilot symbol of the receive antenna port i is located, and an
estimation value of a channel between the transmit antenna port j
and the receive antenna port i is H.sub.ij. In this case, the
estimation value, calculated by the calculation unit 03, of the
channel between the transmit antenna port j and the receive antenna
port i is specifically: H.sub.ij=[r.sup.i.sub.0, r.sup.i.sub.1, . .
. , r.sub.in][b.sup.j.sub.0, b.sup.j.sub.1, . . . ,
b.sup.j.sub.n].sup.T/w.sub.j.
Further, all the units distinguish, in a code division manner,
primary pilot symbols that are on different transmit antenna ports
and are sent by the transmit end.
In this embodiment of the present disclosure, an obtaining unit
obtains receive values at time-frequency resource locations at
which primary pilot symbols sent from each transmit antenna port to
each receive antenna port are located, where interference caused by
other data symbols to the primary pilot symbols is cancelled for
the receive values by using the pilot sending method, designed at a
transmit end, in the foregoing embodiment. Then, because an FBMC
system is a non-orthogonal system, a determining unit needs to
determine a receiving sequence from each transmit antenna port to
each receive antenna port. Finally, a calculation unit calculates
an estimation value of a channel between the transmit antenna port
and the receive antenna port according to the received receive
values and the receiving sequence. With reference to the pilot
sending apparatus in the foregoing embodiment of the present
disclosure, the channel estimation apparatus in this embodiment of
the present disclosure can effectively decrease transmit power of
an auxiliary pilot symbol, thereby reducing a power increase caused
by an auxiliary pilot symbol, and optimizing channel estimation
performance.
Referring to FIG. 11, FIG. 11 is a schematic structural diagram of
another channel estimation apparatus disclosed in this embodiment
of the present disclosure. The channel estimation apparatus shown
in FIG. 10 is obtained by further optimizing the channel estimation
apparatus shown in FIG. 10. Specifically, as shown in FIG. 11, the
apparatus includes the following units: an obtaining unit 01,
determining unit 02, and calculation unit 03.
The obtaining unit 01 is configured to obtain receive values at
time-frequency resource locations at which primary pilot symbols
sent from each transmit antenna port to each receive antenna port
are located, where interference caused by other data symbols to the
primary pilot symbols is cancelled for the receive values by using
auxiliary pilot symbols.
The determining unit 02 includes:
a first obtaining unit 021, configured to obtain an interference
response matrix for the time-frequency resource locations at which
the primary pilot symbols at a transmit end are located;
a second obtaining unit 022, configured to obtain a transmit matrix
that includes transmit values of primary pilot symbols at the
transmit end; and
a first calculation unit 023, configured to calculate the receiving
sequence from each transmit antenna port to each receive antenna
port according to the interference response matrix and the transmit
matrix.
The calculation unit 03 includes:
a third calculation unit 031, configured to: for each transmit
antenna port to each receive antenna port, calculate a product of
row vectors that include the receive values obtained by the
obtaining unit that are of the primary pilot symbols and column
vectors that include the receiving sequence that is determined by
the determining unit and is of the transmit antenna port; and
a fourth calculation unit 032, configured to: calculate a ratio of
a result calculated by the third calculation unit to pilot channel
estimation gain power of the transmit antenna port, and use the
ratio as an estimation value of a channel between the transmit
antenna port and the receive antenna port.
The pilot channel estimation gain power indicates a ratio of joint
pilot power for performing channel estimation by a receive end to
power of a pilot symbol sent by the transmit end.
The first obtaining unit 021 includes:
a first receiving unit, configured to receive an interference
response matrix indication message sent by the transmit end;
and
a first determining unit, configured to determine the interference
response matrix for the time-frequency resource locations of the
primary pilot symbols at the transmit end according to the
interference response matrix indication message.
In another optional implementation manner, the first obtaining unit
021 includes:
a second determining unit, configured to determine time-frequency
resource locations, in a pilot symbol group, at which the primary
pilot symbols at the transmit end are interfered with; and
a second obtaining unit, configured to: obtain interference
coefficient values of interference caused at the determined
time-frequency resource locations in the pilot symbol group to the
primary pilot symbols, and construct the interference response
matrix by using the interference coefficient values.
The second determining unit is specifically configured to: for each
primary pilot symbol in the pilot symbol group, determine,
according to multiplex converter response data and time-frequency
resource locations of the primary pilot symbols, the time-frequency
resource locations at which the primary pilot symbols are
interfered with.
The second determining unit in the first obtaining unit 021
includes:
a second receiving unit, configured to receive an interference
indication message sent by the transmit end; and
a third determining unit, configured to determine the
time-frequency resource locations, in the pilot symbol group, at
which the primary pilot symbols at the transmit end are interfered
with.
The second obtaining unit in the first obtaining unit 021
includes:
a third receiving unit, configured to receive an interference
coefficient table indication message sent by the transmit end;
and
a third obtaining unit, configured to: obtain the interference
coefficient values, in the interference coefficient table
indication message, of the interference caused at the determined
time-frequency resource locations to the primary pilot symbols; and
construct the interference response matrix by using the
interference coefficient values.
Specifically, for detailed processes in which the channel
estimation apparatus calculates estimation values of channels
between the receive end and two transmit antenna ports in a
1.times.2 MIMO-FBMC system and calculates, by using four transmit
antenna ports as an example, an estimation value of a channel
between the transmit antenna ports and the receive end, refer to
content described in the disclosure embodiment corresponding to
FIG. 5.
With reference to the pilot sending apparatus in the foregoing
embodiment, the channel estimation apparatus in this embodiment of
the present disclosure brings beneficial effects from three
aspects: First, pilot overheads are reduced. Compared with an IAM
solution, the pilot overheads are reduced by 60%. Second, a power
increase of an auxiliary pilot symbol is reduced. Statistically, a
power increase of an auxiliary pilot is reduced by
.gamma..gamma..times. ##EQU00019## For example, a power increase of
an auxiliary pilot is reduced by 24% for an IOTA filter. Third,
channel estimation performance is improved. FIG. 7 shows a
throughput emulation result (FBMC vs OFDM_Throughput_UMi-UEspeed)
of an FBMC system that uses the pilot solution in the present
disclosure. The FBMC system can obtain more accurate channel
estimation, and can ensure that about 15% gains are brought to an
FBMC link because a power increase of an auxiliary pilot symbol and
pilot overheads are reduced.
An embodiment of the present disclosure provides a computer storage
medium. The computer storage medium stores a program, and when the
program is executed, FBMC-based pilot sending methods described in
the foregoing embodiments of the present disclosure are
performed.
An embodiment of the present disclosure provides a computer storage
medium. The computer storage medium stores a program, and when the
program is executed, channel estimation methods described in the
foregoing embodiments of the present disclosure are performed.
FIG. 12 is a schematic structural diagram of a sending device
disclosed in an embodiment of the present disclosure. As shown in
FIG. 12, the sending device includes a processor 101, at least one
transmit antenna port 103 (one transmit antenna port is used as an
example in FIG. 12) connected to the processor 101 by using a bus
102, and a memory 104 connected to the processor 101 by using the
bus 102. The memory 104 stores a group of program code, and the
processor 101 is configured to invoke the program code stored in
the memory 104 to perform the following operations:
for each transmit antenna port, inserting a pilot symbol group at
four consecutive FBMC time-frequency resource locations, where the
pilot symbol group includes two auxiliary pilot symbols and two
primary pilot symbols;
for each primary pilot symbol, determining a time-frequency
resource location range in which the primary pilot symbol is
interfered with;
for each primary pilot symbol, obtaining transmit values of data
symbols at time-frequency resource locations in the determined
time-frequency resource location range corresponding to the primary
pilot symbol;
for each primary pilot symbol, obtaining, according to multiplex
converter response data, interference coefficient values of
interference caused at the time-frequency resource locations to the
primary pilot symbol, where the time-frequency resource locations
are in the determined time-frequency resource location range
corresponding to the primary pilot symbol;
calculating a transmit value of each auxiliary pilot symbol in the
pilot symbol group according to the obtained interference
coefficient values and the obtained transmit values of the data
symbols corresponding to each primary pilot symbol; and
sending the pilot symbol group, where the pilot symbol group
includes the calculated transmit values of the auxiliary pilot
symbols.
The inserting, by the processor 101, a pilot symbol group at four
consecutive FBMC time-frequency resource locations includes:
respectively inserting a first auxiliary pilot symbol, a first
primary pilot symbol, a second primary pilot symbol, and a second
auxiliary pilot symbol at the K.sup.th, the (K+1).sup.th, the
(K+2).sup.th, and the (K+3).sup.th FBMC symbol locations on a same
subcarrier at the time-frequency resource locations, where K is a
natural number; or respectively inserting a first auxiliary pilot
symbol, a first primary pilot symbol, a second primary pilot
symbol, and a second auxiliary pilot symbol on the N.sup.th, the
(N+1).sup.th, the (N+.sup.2).sup.th, and the (N+3).sup.th FBMC
subcarriers at a same FBMC symbol location at the time-frequency
resource locations, where N is a natural number.
In an optional implementation manner, the determining, by the
processor 101, a time-frequency resource location range in which
the primary pilot symbol is interfered with includes:
for each primary pilot symbol in the pilot symbol group,
determining, according to the multiplex converter response data and
a time-frequency resource location of the primary pilot symbol, the
time-frequency resource location range in which the primary pilot
symbol is interfered with.
In an optional implementation manner, the determining, by the
processor 101, a time-frequency resource location range in which
the primary pilot symbol is interfered with includes:
obtaining a preset time-frequency resource location range in which
the primary pilot symbol is interfered with.
In an optional implementation manner, the determining, by the
processor 101, a time-frequency resource location range in which
the primary pilot symbol is interfered with includes:
determining, based on an interference estimation algorithm, the
time-frequency resource location range in which the primary pilot
symbol is interfered with.
The calculating, by the processor 101, a transmit value of each
auxiliary pilot symbol in the pilot symbol group according to the
obtained interference coefficient values and the obtained transmit
values of the data symbols corresponding to each primary pilot
symbol includes:
for an auxiliary pilot symbol adjacent to the primary pilot symbol
in the pilot symbol group, adding up values obtained after
separately multiplying the obtained transmit values of the data
symbols corresponding to the primary pilot symbol and the
interference coefficient values of the interference caused at the
time-frequency resource locations of the data symbols to the
primary pilot symbol, and using the calculated added result as a
first result;
dividing the first result by an interference coefficient value of
interference caused at a time-frequency resource location of the
auxiliary pilot symbol to the primary pilot symbol, and using the
calculated result as a second result; and
determining a value obtained after the second result is negated as
the transmit value of the auxiliary pilot symbol.
Specifically, the processor 101 may calculate transmit values of
the first auxiliary pilot symbol and the second auxiliary pilot
symbol with reference to the formula (3). Further, the processor
101 sends primary pilot symbols on different transmit antenna ports
in a code division manner.
In this embodiment of the present disclosure, a sending device
inserts a pilot symbol group on a transmit antenna port, where two
auxiliary pilot symbols and two primary pilot symbols in the pilot
symbol group are sequentially inserted at corresponding
time-frequency resource locations. Then, for each primary pilot
symbol, the sending device separately obtains a time-frequency
resource location range in which the primary pilot symbol is
interfered with and transmit values of data symbols at
time-frequency resource locations in the time-frequency resource
location range; determines, according to multiplex converter
response data, interference coefficient values caused at the
time-frequency resource locations in the time-frequency resource
location range to the primary pilot symbol; and determines a
transmit value of an auxiliary pilot symbol adjacent to the primary
pilot symbol according to the transmit values of the data symbols
in the time-frequency resource location range and the corresponding
interference coefficient values. Therefore, after the pilot symbol
group (the pilot symbol group includes the calculated transmit
values of the auxiliary pilot symbols) is sent, interference caused
by the data symbols at the time-frequency resource locations in the
time-frequency resource location range to the primary pilot symbol
is effectively cancelled for a transmit value that is obtained by a
receive end and is at a time-frequency resource location at which
the primary pilot symbol is located, thereby laying a foundation
for improving channel estimation performance. In addition, a power
increase can be effectively reduced by using auxiliary pilot
symbols respectively adjacent to the two primary pilot symbols in
the pilot symbol group.
Referring to FIG. 13, FIG. 13 is a schematic structural diagram of
a receiving device disclosed in an embodiment of the present
disclosure. As shown in FIG. 13, the receiving device includes a
processor 105, at least one receive antenna port 107 (one receive
antenna port is used as an example in FIG. 13) connected to the
processor 105 by using a bus 106, and a memory 108 connected to the
processor 105 by using the bus 106. The memory 108 stores a group
of program code, and the processor 105 is configured to invoke the
program code stored in the memory 108 to perform the following
operations:
obtaining receive values at time-frequency resource locations at
which primary pilot symbols sent from each transmit antenna port to
each receive antenna port are located, where interference caused by
other data symbols to the primary pilot symbols is cancelled for
the receive values by using corresponding auxiliary pilot
symbols;
determining a receiving sequence from each transmit antenna port to
each receive antenna port; and
calculating, for each transmit antenna port to each receive antenna
port, an estimation value of a channel between the transmit antenna
port and the receive antenna port according to the receive values
of the primary pilot symbols and the receiving sequence.
In an optional implementation manner, the determining, by the
processor 105, a receiving sequence from each transmit antenna port
to each receive antenna port includes:
determining, according to an indication message received from a
transmit end, the receiving sequence from each transmit antenna
port to each receive antenna port.
In another optional implementation manner, the determining, by the
processor 105, a receiving sequence from each transmit antenna port
to each receive antenna port includes:
obtaining an interference response matrix for the time-frequency
resource locations at which the primary pilot symbols at a transmit
end are located;
obtaining a transmit matrix that includes transmit values of
primary pilot symbols at the transmit end; and
calculating the receiving sequence from each transmit antenna port
to each receive antenna port according to the interference response
matrix and the transmit matrix.
Specifically, when the interference response matrix of the transmit
end is .GAMMA., the transmit matrix of the transmit end is P, and a
receiving sequence of the transmit antenna port j is
[b.sup.j.sub.0, b.sup.j.sub.1, . . . , b.sup.j.sub.n].sup.T, the
calculating, by the processor 105, the receiving sequence of the
transmit antenna port is specifically:
[b.sup.j.sub.0, b.sup.j.sub.1, . . . ,
b.sup.j.sub.n].sup.T=.GAMMA..sup.-1P.sup.-1 (0, . . . , 0, w.sub.j,
0, . . . , 0).sup.T, where b.sup.j.sub.n is a receiving sequence at
a time-frequency resource location at which the n.sup.th primary
pilot symbol of the transmit antenna port j is located, w.sub.j
indicates pilot channel estimation gain power of the transmit
antenna port j, a quantity of 0s in (0, . . . , 0, w.sub.j, 0, . .
. , 0).sup.T is equal to n-1, w.sub.j in (0, . . . , 0, w.sub.j, 0,
. . . , 0).sup.T appears at the j.sup.th location, and values at
other locations are 0.
Specifically, the calculating, by the processor 105 for each
transmit antenna port to each receive antenna port, an estimation
value of a channel between the transmit antenna port and the
receive antenna port according to the receive values of the primary
pilot symbols and the receiving sequence includes:
for each transmit antenna port to each receive antenna port,
calculating a product of row vectors that include the receive
values of the primary pilot symbols and column vectors that include
the receiving sequence of the transmit antenna port; and
calculating a ratio of the product result to pilot channel
estimation gain power of the transmit antenna port, and using the
ratio as the estimation value of the channel between the transmit
antenna port and the receive antenna port.
Specifically, for each transmit antenna port on each receive
antenna port, when receive values of primary pilot symbols of the
receive antenna port i are separately r.sup.i.sub.0, r.sup.i.sub.1,
. . . , r.sup.i.sub.n, where r.sup.i.sub.n is a receive value at a
time-frequency resource location at which the n.sup.th primary
pilot symbol of the receive antenna port i is located, and an
estimation value of a channel between the transmit antenna port j
and the receive antenna port i is H.sub.ij, the calculating, by the
processor 105, an estimation value of a channel between the
transmit antenna port j and the receive antenna port i is
specifically: H.sub.ij=[r.sup.i.sub.0, r.sup.i.sub.1, . . .
,r.sup.i.sub.n][b.sup.j.sub.0,b.sup.j.sub.1, . . .
,b.sup.j.sub.n].sup.T/w.sub.j.
In an optional implementation manner, the obtaining, by the
processor 105, an interference response matrix for the
time-frequency resource locations of the primary pilot symbols at
the transmit end includes:
receiving an interference response matrix indication message sent
by the transmit end; and
determining the interference response matrix for the time-frequency
resource locations of the primary pilot symbols at the transmit end
according to the interference response matrix indication
message.
In another optional implementation manner, the obtaining, by the
processor 105, an interference response matrix for the
time-frequency resource locations of the primary pilot symbols at
the transmit end includes:
determining time-frequency resource locations, in a pilot symbol
group, at which the primary pilot symbols at the transmit end are
interfered with;
obtaining interference coefficient values of interference caused at
the determined time-frequency resource locations to the primary
pilot symbols; and
constructing the interference response matrix by using the
interference coefficient values.
In an optional implementation manner, the determining, by the
processor 105, time-frequency resource locations, in a pilot symbol
group, at which the primary pilot symbols at the transmit end are
interfered with includes:
for each primary pilot symbol in the pilot symbol group,
determining, according to the multiplex converter response data and
a time-frequency resource location of the primary pilot symbol, the
time-frequency resource location at which the primary pilot symbol
is interfered with.
In another optional implementation manner, the determining, by the
processor 105, time-frequency resource locations, in a pilot symbol
group, at which the primary pilot symbols at the transmit end are
interfered with includes:
obtaining preset time-frequency resource locations at which the
primary pilot symbols are interfered with.
In still another optional implementation manner, the determining,
by the processor 105, time-frequency resource locations, in a pilot
symbol group, at which the primary pilot symbols at the transmit
end are interfered with includes:
receiving an interference indication message sent by the transmit
end; and
determining, according to the interference indication message, the
time-frequency resource locations, in the pilot symbol group, at
which the primary pilot symbols at the transmit end are interfered
with.
Specifically, the obtaining, by the processor 105, interference
coefficient values of interference caused at the time-frequency
resource locations corresponding to the primary pilot symbols to
the primary pilot symbols includes:
obtaining, according to the multiplex converter response data, the
interference coefficient values of the interference caused at the
determined time-frequency resource locations corresponding to the
primary pilot symbols to the primary pilot symbols.
In another optional implementation manner, the obtaining, by the
processor 105, interference coefficient values of interference
caused at the time-frequency resource locations corresponding to
the primary pilot symbols to the primary pilot symbols
includes:
receiving an interference coefficient table indication message sent
by the transmit end; and
obtaining the interference coefficient values, in the interference
coefficient table indication message, of the interference caused at
the determined time-frequency resource locations to the primary
pilot symbols.
The receiving device distinguishes, in a code division manner,
primary pilot symbols that are on different transmit antenna ports
and are sent by the transmit end.
In this embodiment of the present disclosure, a receiving device
first obtains receive values at time-frequency resource locations
at which primary pilot symbols sent from each transmit antenna port
to each receive antenna port are located, where interference caused
by other data symbols to the primary pilot symbols is cancelled for
the receive values by using the pilot sending method, designed at a
transmit end, in the foregoing embodiment. Then, because an FBMC
system is a non-orthogonal system, the receiving device needs to
determine a receiving sequence from each transmit antenna port to
each receive antenna port. Finally, the receiving device calculates
an estimation value of a channel between the transmit antenna port
and the receive antenna port according to the received receive
values and the receiving sequence. With reference to the sending
device in the foregoing embodiment of the present disclosure, by
using the receiving device in this embodiment of the present
disclosure, transmit power of an auxiliary pilot symbol can be
effectively decreased, thereby reducing a power increase caused by
an auxiliary pilot symbol, and optimizing channel estimation
performance.
It should be noted that, for brief description, the foregoing
method embodiments are represented as a combination of a sequence
of actions. However, a person skilled in the art should appreciate
that the present disclosure is not limited to the described order
of the actions, because according to the present disclosure, some
steps may be performed in other orders or simultaneously. In
addition, a person skilled in the art should also appreciate that
all the embodiments described in the specification are exemplary
embodiments, and the related actions and modules are not
necessarily mandatory to the present disclosure.
Persons of ordinary skill in the art may understand that all or a
part of the steps of the methods in the embodiments may be
implemented by a program instructing relevant hardware. The program
may be stored in a computer readable storage medium. The storage
medium may include a flash memory, a read-only memory (ROM), a
random access memory (RAM), a magnetic disk, and an optical
disk.
The FBMC-based pilot sending method, channel estimation method, and
the related apparatus provided in the embodiments of the present
disclosure are described in detail above. Principles and
implementation manners of the present disclosure are described in
this specification by using specific examples. The descriptions
about the embodiments are merely provided to help understand the
method and core ideas of the present disclosure. In addition, a
person of ordinary skill in the art can make modifications to a
specific implementation manner and an application scope according
to the ideas of the present disclosure. In conclusion, the content
of this specification shall not be construed as a limitation on the
present disclosure.
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